Tag Archives: CentOS

How to secure server with iptables?

Hi there! In this tutorial I would like to show you how to increase server security by using iptables as a firewall. To be honest, not many people are actually using iptables or any firewall. I think that this is bad practice, because you they allow all traffic to go in and out. You should always limit the possible entry points to your server.

Firewalld vs iptables

Since CentOS 7, we have new tool called firewalld. This is not actually an alternative to iptables. firewalld is a wrapper for iptables. Many people say, that it's easier to use than iptables, but to be honest I believe that it's not flexible enough. Maybe I'm wrong, but I'd love to see some advanced example, how to transform iptables rules below to firewalld 🙂 If you want to use firewalld instead of iptables, unfortunately you need to read different tutorial. Here is great article about firewalld from DigitalOcean.

How to install iptables on CentOS7?

Before we will install iptables, we need to get rid of firewalld first :

sudo yum remove firewalld -y

Next, we can install iptables:

sudo yum install iptables iptables-services -y

iptables-services is simple script that will help us save and restore firewall rules.

Secure iptables rules for CentOS

First, let's check if there are any rules by executing following command:

sudo iptables -S

If you will get following output:

-P INPUT ACCEPT
-P FORWARD ACCEPT
-P OUTPUT ACCEPT

It means that you allow all traffic, both incoming and outgoing to your server. However if you have anything more than output above, copy it to separate file as a backup.

The easiest way of adding rules is by editing iptables rules file. Open the file, or create one if it doesn't exists:

sudo vi /etc/sysconfig/iptables

I will describe whole file line by line, but at the bottom of this post you can find whole content that I'm using for iptables.

Opening and closing tags

*filter

File must contains two indicators:

start of the ruleset *filter
end of the ruleset COMMIT

You need to have both in order to get iptables configured properly. Between these two lines, you can add iptables rules.

Clear all existing rules

-X
-F
-Z

At the very beginning I'd like to clear whole rules. In other words - enable all traffic. The reason is that I want to be able to execute that file over and over again, and I will always set the rules that I have in file. No other rules will be applied (for instance rules added by command line).

Allowing loopback

-A INPUT -i lo -j ACCEPT
-A OUTPUT -o lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT
-A OUTPUT -d 127.0.0.0/8 -j REJECT

Next thing is to allow all loopbacks. Those are local connection and blocking them might cause errors in some connections. In addition we will block those which doesn't use lo0.

Keep established connections

-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

All connections that are active now, should remain untouched. It will prevent from interruption of services.

PING command

-A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT
-A INPUT -p icmp --icmp-type echo-reply -j ACCEPT
-A INPUT -p icmp --icmp-type echo-request -j ACCEPT
-A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT

In most cases you will need to be able to ping server. These rules will allow two things. First - you'll be able to ping your own server. Second - you will be able to execute ping from your server. Both are usually needed and quite useful.

Protection from PING of Death attack

-N PING_OF_DEATH
-A PING_OF_DEATH -p icmp --icmp-type echo-request -m hashlimit --hashlimit 1/s --hashlimit-burst 10 --hashlimit-htable-expire 300000 --hashlimit-mode srcip --hashlimit-name t_PING_OF_DEATH -j RETURN
-A PING_OF_DEATH -j DROP
-A INPUT -p icmp --icmp-type echo-request -j PING_OF_DEATH

Ping is cool, however you might get attacked with Ping of Death attack. Here is simple protection.

Prevent some nasty attacks

-N PORTSCAN
-A PORTSCAN -p tcp --tcp-flags ACK,FIN FIN -j DROP
-A PORTSCAN -p tcp --tcp-flags ACK,PSH PSH -j DROP
-A PORTSCAN -p tcp --tcp-flags ACK,URG URG -j DROP
-A PORTSCAN -p tcp --tcp-flags FIN,RST FIN,RST -j DROP
-A PORTSCAN -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
-A PORTSCAN -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL ALL -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL NONE -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL FIN,PSH,URG -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL SYN,FIN,PSH,URG -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP
-A INPUT -f -j DROP
-A INPUT -p tcp ! --syn -m state --state NEW -j DROP

This is really nice piece of rules that will prevent port scanning, SYN flood attacks, invalid packages, malformed XMAS packets, NULL packets, etc.

UDP traffic

-A INPUT -p udp --sport 53 -j ACCEPT
-A OUTPUT -p udp --dport 53 -j ACCEPT
-A INPUT -p udp --sport 123 -j ACCEPT
-A OUTPUT -p udp --dport 123 -j ACCEPT

I enable usually only ports for outgoing traffic (from our server to outside world). There are two ports that I'd like to open:

53 - DNS port. It's a must if you want to use curl or yum. If you will have it closed, you will not resolve any domain name.
123 - NTP port. If you are using chrony or ntpd, you need to enable that port to allow NTP deamon synchronisation.

TCP traffic

# Open TCP ports for incoming traffic
-A INPUT -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
-A INPUT -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
-A INPUT -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT

# Open TCP ports for outgoing traffic
-A INPUT -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
-A INPUT -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
-A INPUT -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT

With TCP it's more complicated, but it's not that hard. First, you need to think what traffic you need to access from your server (outgoing traffic). I usually allow only SSH, HTTP and HTTPS traffic. Yum requires HTTP and HTTPS ports for pulling new packages. You will need it also for wget or curl. SSH is not mandatory, but if you want to pull packages from git via ssh protocol, you will need it as well.

I usually enable the same for incoming traffic. If you have httpd or nginx installed, you need to enable port 80. If you are using SSL for HTTPS, you need to enable 443 also. In addition to these two ports you must enable port 22 for SSH. If you will block this, you won't be able to get access to your server!

Block everything else

-A INPUT -j DROP
-A FORWARD -j DROP
-A OUTPUT -j DROP

At the very end, before closing COMMIT tag I add these three rules. So everything that was not specified above will be dropped. Both incoming and outgoing traffic.

How to apply rules?

There are two ways how you can apply the rules. First, save the changes in iptables file. First method is not permanent method. It's good way of testing your firewall before saving them permanently. If anything will go wrong, you can just restart the server and you will have all traffic open. Make sure that you check SSH access with these rules. Log out and try to login after applying rules.

So non permanent way of applying rules is:

sudo iptables-restore < /etc/sysconfig/iptables

Try to check rules with iptables -S to see the difference:) Check if everything is working fine. If so, you can set them permanently. After each server restart, rules will be applied automatically.

sudo systemctl start iptables.service
sudo systemctl enable iptables.service

If you want to reload rules, simply edit the file, add what you need and restart iptables service:

sudo systemctl restart iptables.service

You can use our Ansible LAMP on Steroids project to make configuration of your server easier!

It is based on Ansible. If you don't know what Ansible is, check our tutorial first.

Clone our repository and setup your server faster with LAMP on steroids.

Whole content of iptables rules

*filter

# Clear all iptables rules (everything is open)
-X
-F
-Z

# Allow loopback interface (lo0) and drop all traffic to 127/8 that doesn't use lo0
-A INPUT -i lo -j ACCEPT
-A OUTPUT -o lo -j ACCEPT
-A INPUT -d 127.0.0.0/8 -j REJECT
-A OUTPUT -d 127.0.0.0/8 -j REJECT

# Keep all established connections
-A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
-A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

# Allow ping
-A OUTPUT -p icmp --icmp-type echo-request -j ACCEPT
-A INPUT -p icmp --icmp-type echo-reply -j ACCEPT
-A INPUT -p icmp --icmp-type echo-request -j ACCEPT
-A OUTPUT -p icmp --icmp-type echo-reply -j ACCEPT

# Protect from ping of death
-N PING_OF_DEATH
-A PING_OF_DEATH -p icmp --icmp-type echo-request -m hashlimit --hashlimit 1/s --hashlimit-burst 10 --hashlimit-htable-expire 300000 --hashlimit-mode srcip --hashlimit-name t_PING_OF_DEATH -j RETURN
-A PING_OF_DEATH -j DROP
-A INPUT -p icmp --icmp-type echo-request -j PING_OF_DEATH

# Prevent port scanning
-N PORTSCAN
-A PORTSCAN -p tcp --tcp-flags ACK,FIN FIN -j DROP
-A PORTSCAN -p tcp --tcp-flags ACK,PSH PSH -j DROP
-A PORTSCAN -p tcp --tcp-flags ACK,URG URG -j DROP
-A PORTSCAN -p tcp --tcp-flags FIN,RST FIN,RST -j DROP
-A PORTSCAN -p tcp --tcp-flags SYN,FIN SYN,FIN -j DROP
-A PORTSCAN -p tcp --tcp-flags SYN,RST SYN,RST -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL ALL -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL NONE -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL FIN,PSH,URG -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL SYN,FIN,PSH,URG -j DROP
-A PORTSCAN -p tcp --tcp-flags ALL SYN,RST,ACK,FIN,URG -j DROP

# Drop fragmented packages
-A INPUT -f -j DROP

# SYN packets check
-A INPUT -p tcp ! --syn -m state --state NEW -j DROP

# Open ports for outgoing UDP traffic
-A INPUT -p udp --sport 53 -j ACCEPT
-A OUTPUT -p udp --dport 53 -j ACCEPT
-A INPUT -p udp --sport 123 -j ACCEPT
-A OUTPUT -p udp --dport 123 -j ACCEPT


# Open TCP ports for incoming traffic
-A INPUT -p tcp --dport 22 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --sport 22 -m state --state ESTABLISHED -j ACCEPT
-A INPUT -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
-A INPUT -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT

# Open TCP ports for outgoing traffic
-A INPUT -p tcp --sport 80 -m state --state ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --dport 80 -m state --state NEW,ESTABLISHED -j ACCEPT
-A INPUT -p tcp --sport 443 -m state --state ESTABLISHED -j ACCEPT
-A OUTPUT -p tcp --dport 443 -m state --state NEW,ESTABLISHED -j ACCEPT


# Drop all other traffic
-A INPUT -j DROP
-A FORWARD -j DROP
-A OUTPUT -j DROP

COMMIT

What's next?

We secured our system with basic firewall. That will increase the security of our server. In one of the next episodes we will change the configuration of our SSH and therefore make it more secure.

As always You can use our Ansible playbook for faster provisioning of our server. You can find it on GitHub.

How to install and configure latest version of MySQL on CentOS?

1 Reply

Hi there! Today I want to show you how to install latest version of MySQL Community server (5.7.16) on CentOS 7. I will show you how to install it, set root password, configure server and optimize it for performance. Also I will show you how to create databases and assign users to them.

How to install MySQL on CentOS in latest version

When you try to install MySQL on bare CentOS, you will actually install MariaDB (fork of MySQL) instead. It comes with version 5.5.* It's up to you what you want to use, but I prefer MySQL. Especially 5.7 version. There is great performance boost and lot of new features added, comparing to 5.5 or 5.6.

If you have any data on MySQL, it's best to create a backupof data, before you will change anything. Here is a tutorial how to perform backup of MySQL databases.

Before you will actually install MySQL, make sure that MariaDB is not installed. You can just remove it. TIP: removing MariaDB will not remove any databases. It will remain on your hard drive.

sudo yum remove mariadb -y

So let's get to installation. First you need to enable MySQL repository. It's easy by adding following file to yum repositories:

sudo vi /etc/yum.repos.d/mysql-community.repo

and place there following content:

[mysql57-community]
name=MySQL 5.7 Community Server
baseurl=http://repo.mysql.com/yum/mysql-5.7-community/el/7/$basearch/
enabled=1
gpgcheck=1
gpgkey=http://dev.mysql.com/doc/refman/5.7/en/checking-gpg-signature.html

Save the changes. It will enable MySQL repository where from you can install latest version.

Installation is pretty easy:

sudo yum install mysql-community-server -y

That's it! You have MySQL installed in latest version!

Setting root password in MySQL

Setting root password for MySQL is important. You should not leave your database server unprotected, even if you only plan to use localhost connection.

Before you will start anything, make sure that MySQL is up and running:

sudo systemctl start mysqld

If this is fresh installation of MySQL (MariaDB or older version of MySQL was never installed) , MySQL will generate temporary password.

You can find it by using following command:

grep 'temporary password' /var/log/mysqld.log

You will get random password, for instance something like wG]_xj8tus. This is current password to root account. Keep in mind that this is only temporary password. It will expire, so you need to change it as soon as possible.

In order to change root password I like to use mysqladmin tool. So execute following command:

mysqladmin -u root -pwG]_xj8tus password NEW_STRONG_ROOT_PASSWORD

You need to replace wG]_xj8tus with the password from grepping log file. Note that there is no space after -p argument. Also replace NEW_STRONG_ROOT_PASSWORD with your new root password. Keep in mind, that it needs to be strong password, containing lower and upper case characters, numbers and special characters. MySQL 5.7 comes with plugin that validates password strength. It won't allow you changing password to something that is easy to guess or brute force.

If you just upgrading MySQL/MariaDB, your root password will be the same. You can of course change it with mysqladmin if you wish.

However if you are upgrading from MySQL/MariaDB version prior to 5.7 it's nice to execute following command:

mysql_upgrade -u root -p

Type your root password. It will check all the data and alter tables for 5.7 rules.

You might ask - how about mysql_secure_installation? You can also use this command for setting root password after installation. However when you install fresh version of MySQL 5.7 there is no test database, anonymous users etc. Everything is clean and secured.

Configuration of MySQL 5.7

I like to tune up default MySQL configuration. With 5.7 version, lot of defaults are set in order to provide high security and performance. However there are few things I like to change. Most of the stuff is stored under /etc/my.cnf file. MySQL is reading configuration from there during startup. You can also change it dynamically, but here I will focus only on this file.

Edit the file first:

sudo vi /etc/my.cnf

There will be some defaults, you can leave them as they are. Most probably, all options here will be missing, so you need to add them under [mysqld] section.

Temporary in-memory tables

tmp-table-size=32M
tmp-heap-table-size=32M

I increase the size of temporary in-memory tables created by MySQL. If you are doing lot of advanced GROUP BY queries, you will probably have to increase it. Make sure that you are setting both to the same value. If one will be lower, second one will be limited to lower value as well.

Query caching

Query caching is disabled by default. It caches result sets from most frequent queries to database. It usually give nice performance boost to MySQL server:

query-cache-type=1
query-cache-size=32M

InnoDB buffer

Also another performance boost is creating buffer for InnoDB pools. It will keep the data in RAM, so reads will be much faster. Make sure to not to set these values higher than your RAM limits. It should be large enough to store as much data as possible.

innodb-buffer-pool-instances=1
innodb-buffer-pool-size=128M

Logging slow queries

Slow queries can kill your server. It's nice to know earlier that something is going on. I usually turn this on and check it frequently for such queries. If there are some complicated / not optimal queries, you should fix them as soon as possible.

slow-query-log=1
slow-query-log-file=/var/lib/mysql/localhost-slow-query.log<

TIMESTAMP fields behavior

If you would check MySQL log during startup, you can note that there is a warning regarding TIMESTAMP fields. You can read more about these changes here. If you want to suppress that warning, use following option

explicit-defaults-for-timestamp=1

In order to apply changes, you need to restart MySQL daemon:

sudo systemctl restart mysqld

Few notes about playing with configuration. You must know that it's not easy and it's highly depends on number of tables, queries, inserts and lot of other factors. I usually use two tools. First is MySQLTuner that can get you some insights about what to change in order to gain performance. Usually it's just tuning query cache, and InnoDB buffer size. However practice shows that it doesn't always show correct values. Sometimes you can get slower performance instead.

So I use other tool - Datadog. You can also use New Relic, or any other monitoring tool that generates charts. So I usually change one thing at the time. I'm restarting MySQL server and waiting around 48h to see if it's actually performing better or not. This might seem to be slow approach but it's definitely safe:)

But before you start to playing with your configuration, make sure that you don't have slow queries or large tables that you scan without indexes. Sometimes just adding index will reduce query time. No need to change MySQL configuration files:)

MySQL group

MySQL during installation create it's own group - mysql. Most of the data files, and logs have mysql:mysql ownership. It makes it hard to read the logs when you are non-root user. You need to use sudo to get access to logs. You can make it simpler by adding user to mysql group. When user will be in such group, he can easily read logs. In my case, user is named developer.

sudo usermod -a -G mysql developer

Create databases and users

Probably the most important part from MySQL user is how to create database and users? First login to MySQL with your root account:

mysql -u root -p

And then start with creating databases. You need to enter following query:

CREATE DATABASE database_name_here;

Replace database_name_here with your database name. I like to create name for database from domain. So for instance for blacksaildivision.com, database name would be blacksaildivision. Remember that you can't use the . in database name.

Once you have your database, you should create dedicated user that only has access to this database. Having separate user per database is good approach from security perspective.

In order to create user in database execute following query:

CREATE USER 'blacksaildivision'@'localhost' IDENTIFIED BY 'NotEasyToGuessPassword123^#';

It will create blacksaildivision user that can connect to MySQL server only via localhost. It means that he won't have access from outside. After IDENTIFIED BY you need to type password for user you want to create. Same rules as for root password, it can't be easy to guess.

After user is created it's time to give him access to database you created before. Query goes like this:

GRANT ALL PRIVILEGES ON blacksaildivision.* TO 'blacksaildivision'@'localhost';

So you give user full access to blacksaildivision database. .* means that he should have access to all tables in blacksaildivision database. After TO you need to specify user that you created in step before.

To apply privileges, you need to reload them. Fire following query:

FLUSH PRIVILEGES;

And that's it! Create as many databases and users as you wish:) You can test connection to database with new credentials from command line. First exit from current MySQL session and than use following command:

mysql -u blacksaildivision -p blacksaildivision

-u stands for user, -p means that user will connect by using password. Last thing is database name you want to connect to.

Start MySQL on system boot

Last thing is to add MySQL to boot list. So after CentOS will start, MySQL will start as well:

sudo systemctl enable mysqld

Remember that you can use our lamponsteroids project based on Ansible that will automate whole server setup:)

PHP – how to install from source on CentOS

10 Replies

In this tutorial I would like to show you how to install latest version of PHP on CentOS 7. If you are using PHP you most probably will want to have latest version of PHP7. PHP 5 support officially ends this year. Version 7 is now commonly used. It gives lot of performance boost and new features.

Unfortunately default version that comes from repo in CentOS 7 is PHP 5.4, so you can't use yum command without any custom repo like remi. Including custom repository is one way of installing desired PHP version. Another option is to compile it from source code. This tutorial will show you how to do that. It's not as hard as it might sounds:)

Install required tools for compilation

In order to compile PHP from source you need to install few tools and libraries. First you need EPEL repository to be enabled. This repository contains more recent version of packages. Most probably you have it installed already, but just to be sure, execute following command:

sudo yum install epel-release -y

Once you have it installed execute following command to install required packages:

sudo yum install autoconf libtool re2c bison libxml2-devel bzip2-devel libcurl-devel libpng-devel libicu-devel gcc-c++ libmcrypt-devel libwebp-devel libjpeg-devel openssl-devel -y

Download and unpack PHP Source code

Next step is downloading PHP source code. Easiest option is to download it from GitHub PHP releases. Choose the version you would like to install. In my case it's 7.2.3. Copy link to tar.gz archive and execute following commands:

curl -O -L https://github.com/php/php-src/archive/php-7.2.3.tar.gz
tar -zxvf php-7.2.3.tar.gz
cd php-src-php-7.2.3

It will download the archive from GitHub, unpack the sources and change working directory to unpacked sources.

Compile PHP

Now it's time to compile PHP. First we need to build configure command. In order to do that execute following command:

./buildconf --force

Once configure command is created we can use it to configure PHP installation. This process will enable certain PHP extensions such as PDO, FPM, OPCache, GD library etc. If you need any libraries that are not provided here, you can execute ./configure --help option and check if there is something you need. Following command will install PHP with most common extensions:

./configure --prefix=/usr/local/php --enable-fpm --disable-short-tags --with-openssl --with-pcre-regex --with-pcre-jit --with-zlib --enable-bcmath --with-bz2 --enable-calendar --with-curl --enable-exif --with-gd --enable-intl --enable-mbstring --with-mysqli --enable-pcntl --with-pdo-mysql --enable-soap --enable-sockets --with-xmlrpc --enable-zip --with-webp-dir --with-jpeg-dir --with-png-dir

Apart from enabling extensions command above will also set where PHP will be installed. In my case it's /usr/local/php location. If you will want to remove compiled PHP you will simply have to remove entire directory given under --prefix option.

Next it's time to compile PHP. Please be aware that it takes few minutes:

make clean
make

Install compiled PHP

Once PHP is compiled it is time to install it. Simply execute following command:

sudo make install

PHP Configuration

PHP-FPM setup

Before we will be able to run PHP from Apache we need to setup PHP-FPM worker. After installation there should be PHP-FPM default configuration file in installation directory. We will alter the file and then change it a bit.

cd /usr/local/php/etc
mkdir fpm.d
cp php-fpm.conf.default php-fpm.conf
vi php-fpm.conf

We need to uncomment/change these lines:

include=etc/fpm.d/*.conf
pid = /var/run/php-fpm.pid
error_log = log/php-fpm.log

COPY EVERYTHING UNDER Pool Definitions TO CLIPBOARD AND REMOVE IT FROM php-fpm.conf FILE
;;;;;;;;;;;;;;;;;;;;
; Pool Definitions ;
;;;;;;;;;;;;;;;;;;;;

include=/etc/fpm.d/*.conf - by default there is one pool defined inside php-fpm.conf file. The best way to solve it is the same way as we solved Apache vhosts. We will include each pool in separate directory. In php-fpm.conf file one pool is already defined. We need to delete it from this file and put it inside fpm.d directory. We will have better control over the pools. The easiest way is just to Cut it from this file and paste it into new one.

Now let's create the file inside fpm.d for our example.com domain:

cd fpm.d
vi example.com.conf

PASTE TEXT FROM CLIPBOARD HERE AND CHANGE THESE LINES:

[www] -> [example_com] //Must be unique per file
user = apache
group = www
listen = 127.0.0.1:9000 //Port must be unique per file
catch_workers_output = yes
slowlog = /var/www/example.com/logs/php-fpm.slow.log
request_slowlog_timeout = 30s
php_flag[display_errors] = off
php_admin_value[error_log] = /var/www/example.com/logs/php-fpm.error.log
php_admin_flag[log_errors] = on
php_admin_value[memory_limit] = 64M
php_admin_value[open_basedir] = /var/www/example.com/htdocs

Each pool must have different name. So we need to change it from [www] to something else, for instance to domain name. It'll be easier to find the issues inside log files.

We set user and group to the same user as apache to have access to files.

Port will be different per pool. Standard way is to start from port 9000. Next will be 9001 etc.

We will catch errors and log them to file. In addition we set logging for slow requests.

Nice part is that we can overwrite the settings from php.ini here. So we can overwrite error_log or memory_limit for instance. We should also set open_basedir so PHP will have access only to files inside our htdocs directory. Our server will be more secure with this setting.

php.ini and OPCache configuration

Second thing is php.ini file. After installation php.ini file should located in /usr/local/php/lib. This is only the location. After compiling from source You won't anything there so we need to copy it from uncompressed sources.

cd /usr/local/php/lib
cp ~/sources/php-5.6.6/php.ini-development ./php.ini
vi php.ini

This is pretty large file with lot of configuration settings. Fortunately we only need to change some of the options:

short_open_tag = On
open_basedir = /var/www
disable_functions = exec,passthru,shell_exec,system,proc_open,popen
expose_php = Off
max_execution_time = 30
memory_limit = 64M
date.timezone = Europe/Warsaw
error_reporting = E_ALL & ~E_DEPRECATED & ~E_STRICT
display_errors = Off
display_startup_errors = Off
log_errors = On
post_max_size = 5M
upload_max_filesize = 4M

opcache.enable=1
opcache.memory_consumption=64
opcache.interned_strings_buffer=16
opcache.max_accelerated_files=7000
opcache.validate_timestamps=0 ;set this to 1 on production server
opcache.fast_shutdown=1

So we set few things here, enable <? tag, limit access to files from PHP level, disabled dangerous functions, adjusts timezone, security, max execution times, errors etc. In addition we have enable OPCache for PHP.

Each one of these options are well commented inside php.ini file. If You don't like the settings here or You need something else, feel free to change it for Your purposes.

Useful shell scripts for PHP

/etc/init.d/php-fpm

As You probably remember during Apache setup we create script so we can use service command to start / stop Apache process. Now we will do the same for PHP-FPM

With PHP source code there comes ready script for that purpose.

cd /etc/init.d
cp ~/sources/php-5.6.6/sapi/fpm/init.d.php-fpm php-fpm
vi php-fpm

Now we need to setup configuration for the file:

prefix=/usr/local/php
exec_prefix=${prefix}

php_fpm_BIN=${exec_prefix}/sbin/php-fpm
php_fpm_CONF=${prefix}/etc/php-fpm.conf
php_fpm_PID=/var/run/php-fpm.pid

Save the file and add executable permission.

chmod +x php-fpm
servcie php-fpm status
service php-fpm start
servcie php-fpm status

After that we should have php-fpm process up and running!

Add PHP to $PATH

We can do one more thing to make our life easier:) Add PHP executable to PATH, so we'll be able to call php command from every directory.

echo 'pathmunge /usr/local/php/bin' > /etc/profile.d/php.sh

Execute such command, log out, log in and You'll be able to execute:

php -v

Setup Apache for PHP-FPM

Now is the time to finally setup Apache for .php files. Let's edit one of the Virtual Hosts now.

vi /usr/local/apache2/conf/vhosts/example.com.conf

<VirtualHost *80>
    ServerName example.com

    <LocationMatch "^/(.*\.php(/.*)?)$">
        ProxyPass fcgi://127.0.0.1:9000/var/www/example.com/htdocs/$1
    </LocationMatch>

////Rest of the file below

So basically we need to proxy all files with .php extension to our PHP-FPM process. Also we need to restart Apache and make sure PHP-FPM is running httpd server:

service php-fpm start
service httpd restart

How to test if PHP is working?

We need to test if our PHP installation works. The easiest way to debug and check what's going on would be to create test.php file inside our /var/www directory.

vi /var/www/example.com/htdocs/test.php

and paste phpinfo() function there:

<?php

phpinfo();

Save the file and open the file in Your browser, assuming that your vagrant setup is correct. For instance http://example.com/test.php or 192.168.99.99/test.php

If everything is OK you should get information about PHP installation. Well done!

What's next

We are one step closer to our LAMP server. The only thing we are missing now is MySQL which we will install in upcoming episodes.

If You are running Ansible for provisioning You can find everything from this series inside my GitHub.

Apache hardening with mod_security

2 Replies

In this part of setup complete webserver we will harden Apache with popular mod_security. Mod_security is a small module that works like application firewall. It protect the app before most common attacks and vulnerabilities. It's good to have such thing on the webserver.

I assume that You have Apache already installed, if not check out previous part - How to install Apache on CentOS?

[sc:lamp_series]

How to install mod_security on Apache httpd server

First thing is installation of required tools. We need them to compile mod_security.

yum install automake libtool libxml2-devel

Next thing that we need is to download and decompress mod_security. Download links can be found on official mod_security page.

cd ~/sources
wget https://www.modsecurity.org/tarball/2.9.0/modsecurity-2.9.0.tar.gz
tar -zxvf modsecurity-2.9.0.tar.gz

Now it's time to compile mod_security. While ./confgure we need to pass paths to axps and apr binaries. All binaries should be inside bin directory in apache installation path.

cd modsecurity-2.9.0
./autogen.sh
./configure --with-apxs=/usr/local/apache2/bin/apxs --with-apr=/usr/local/apache2/bin/apr-1-config --with-apu=/usr/local/apache2/bin/apu-1-config
make
make install
cp /usr/local/modsecurity/lib/mod_security2.so /usr/local/apache2/modules

If there was no error mod_security is ready to use. It can be found in /usr/local/modsecurity We need to copy generated .so file to apache extension directory.

ModSecurity and OWASP rules

mod_security is nothing without the rules that tells what attacks should be blocked. Fortunately there is a great package with lot of rules provided by OWASP. We will use such rules package to harden Apache HTTPD. So let's download, unzip and copy the rules to apache configuration directory.

cd ~/sources
wget -O owasp.tar.gz https://github.com/SpiderLabs/owasp-modsecurity-crs/tarball/master
mkdir /usr/local/apache2/conf/crs
tar -zxvf owasp.tar.gz -C /usr/local/apache2/conf/crs --strip 1
cd /usr/local/apache2/conf/crs
cp modsecurity_crs_10_setup.conf.example modsecurity_crs_10_setup.conf

Now we are ready to use ModSecurity!

ModSecurity configuration

In previous article we added httpd-security.conf file with some basic rules that improves Apache security. We will modify this file to load mod_security with OWASP rules and add some basic configuration. You need to know that mod_security is pretty large module with tons of configuration option. You can find them in ModSecurity reference manual.

vi /usr/local/apache2/conf/extra/httpd-security.conf

Once You open the file add these lines somewhere in the file:

LoadModule security2_module modules/mod_security2.so

<IfModule security2_module>
      Include conf/crs/modsecurity_crs_10_setup.conf
      Include conf/crs/base_rules/*.conf
      # Include conf/crs/experimental_rules/*.conf
      # Include conf/crs/optional_rules/*.conf

      SecRuleEngine On
      SecRequestBodyAccess On
      SecResponseBodyAccess On 
      SecResponseBodyMimeType text/plain text/html text/xml application/octet-stream
      SecDataDir /tmp

      # Debug log
      SecDebugLog /usr/local/apache2/logs/modsec_debug.log
      SecDebugLogLevel 3

      SecAuditEngine RelevantOnly
      SecAuditLogRelevantStatus ^2-5
      SecAuditLogParts ABCIFHZ
      SecAuditLogType Serial
      SecAuditLog /usr/local/apache2/logs/modsec_audit.log
</IfModule>

So from the top:

First we need to load mod_security module.
Next are rules from OWASP that we will include to ModSecurity. We need to include the setup and base rules. OWASP core rule set comes with lot more features that are marked as optional or experimental. We can enable those rules, but we also need to remember that it might not play well with our website. It's rather testing by trial and error then one rule will work well on every website. But in general including base_rules is OK.
SecRuleEngine enables detection and blocking of malicious attacks.
SecRequestBodyAccess enable inspection of data transported request bodies
SeResponseBodyAccess buffer response bodies matched by SecResponseBodyMimeType
SecDataDir working directory for ModSecurity temporary purposes
Next thing is Debug log. By default all error logs goes to apache error log, but we can set different path to debug log. Best practice would be to change it per domain inside particular VirtualHost file. In previous article we setup directory structure and we have logs directory there. It would be wise to used it for debug log as well.
Audit Log is complementary log for Debug log. It has detail information about every error. It's disabled by default so we need to enable it and turn on logging relevant (warnings and errors) issues. Next options are for configuration the audit log. In general there are lot more of discussing at this topic.

If You want to learn more about how to setup and read mod_security logs, here is really great article about mod_security logging by Infosec Institue.

Now we just need to save the file restart apache and our httpd server has better security.

service httpd restart

What's next?

If You are following our series, You should have now part of LAMP stack (Linux Apache MySQL PHP). Apache is secured with mod_security.

Small note to those who would like to install mod_evasive as well to increase the security. To be honest, it's really not worth to install it on Apache. Why? Because when You run multiple instances via MPM mod_evasive doesn't share the info between the MPM instances. It means that one instance of apache can block the attacker but others wont. So if You have many MPM workers mod_evasive is just useless.

As always, if You are using Ansible for server provisioning You can use ready playbook, that will cover everything in this series. You can find it on GitHub.

In next episode we will add P to our LAMP server.

How to install latest Apache HTTPD on CentOS

26 Replies

Hi there! Today I'd like to show you how do I install and configure Apache HTTPD on CentOS 7. I like to have it installed in minimal and secure way. Beware! This is pretty long tutorial covering lot's of aspects from compilation, through configuration, SSL/HTTPS/HTTP2, basic hardening etc.

How to install Apache HTTPD on CentOS using yum - easy way

There are two ways to install Apache HTTPD on CentOS. First is with yum and it is the simplest version:

sudo yum install httpd -y

Volia! You have httpd installed. However, if you check the version:

httpd -v

You will most probably get 2.4.6 version or slightly newer. If you check Apache website, you will note, that they have 2.4.33 version available. So, if you want to have access to latest features such as HTTP/2 support or latest bugfixes, you will have to try more difficult method which is compiling Apache from source. It might seem complicated but it's really not.

OpenSSL - do you have latest version?

If you want to enable HTTP/2 in Apache HTTPD which I strongly recommend for increased performance you need to have latest version of OpenSSL installed in your system. Older version does not support it, so you need to compile new version from source. I have separate tutorial how to install latest OpenSSL - make sure that you follow that first and then get back to this tutorial.

Remove old HTTPD first

Make sure that you don't have httpd installed. On some machines it comes by default, or you might be using older version. In order to avoid complications later I advise you to remove it first. However you must know that if you have some websites online that are using Apache, they will have some downtime before you setup new Apache. Execute following command to remove current Apache httpd from your system:

sudo yum remove httpd -y

Install EPEL

There are lots of different libraries in EPEL, but for compiling Apache HTTPD with HTTP/2 support we need one thing that EPEL provides - libnghttp2

In order to install EPEL repository execute following command:

sudo yum install epel-release -y

Install required tools for compilation

You need to install some tools that will help us compile Apache. It's basic stuff like compiler, required libraries etc:

sudo yum install autoconf expat-devel libtool libnghttp2-devel pcre-devel -y

Download and unpack source code

Next thing that you need are packages with source files. For compiling Apache, you will need 3 different packages - httpd itself, apr and apr-util. Last two are Apache Runtime libraries. They are required for Apache HTTPD.

I like to download packages from GitHub releases. Here are the links to the packages:

Apache httpd - https://github.com/apache/httpd/releases
APR - https://github.com/apache/apr/releases
APR-util https://github.com/apache/apr-util/releases

Click on tar.gz icon, copy the link to package and download them with curl or wget. Or simply copy commands below:

curl -O -L https://github.com/apache/httpd/archive/2.4.33.tar.gz
curl -O -L https://github.com/apache/apr/archive/1.6.3.tar.gz
curl -O -L https://github.com/apache/apr-util/archive/1.6.1.tar.gz

Unpack downloaded sources:

tar -zxvf 2.4.33.tar.gz
tar -zxvf 1.6.3.tar.gz
tar -zxvf 1.6.1.tar.gz

APR and APR-Util

Apache requires APR library for compilation. You need to copy the source codes to correct directory:

cp -r apr-1.6.3 httpd-2.4.33/srclib/apr
cp -r apr-util-1.6.1 httpd-2.4.33/srclib/apr-util

It's important to not to include version number in APR directories. If you just copy apr-1.6.3 without changing the name, it will give you a warning about missing apr directory.

Compile source code

Now you are ready to compile Apache httpd. It's important that you should not use root user for compilation. It can lead to serious security issues. I described it more on my other tutorial about installing GIT. In short words, imagine that you downloaded package from wrong source with malicious code. If you would compile it as root user, anything can happen to your server. Including cutting of your root access. I'm not saying that it's not possible to compile packages as root, because it is. It's just not safe. If you want to create separate user with sudo powers, you can read this tutorial.

So get inside httpd directory and compile your Apache version:

cd httpd-2.4.33
./buildconf
./configure --enable-ssl --enable-so --enable-http2 --with-mpm=event --with-included-apr --with-ssl=/usr/local/openssl --prefix=/usr/local/apache2
make

First command ./buildconf will build ./configure file required for configuration of the build.

./configure command will setup everything for compilation of Apache HTTPD. Here are the options that I use:

--enable-ssl will build Apache with SSL support, so you can enable HTTPS on your websites.
--enable-so will enable dynamically loaded modules. So you can enable and disable modules without recompilation (I will describe modules in configuration part)
--enable-http2 will enable HTTP/2 support.
--with-mpm will set multiprocessing modules for Apache. I'm using event, but you can use worker or prefork instead. event works best for me and I think that it is mpm that will give you most performance.
--with-included-apr It will use APR library that you copied to srclib directory
--with-ssl will point compiler to newer version of OpenSSL. Make sure that you compiled it first!
--prefix is the installation path for Apache httpd compiled package

Whole process might take a while. It depends how fast your server is.

Install HTTPD

After it's compiled you can install it. For that you need sudo or root account:

sudo make install

Apache should be installed in the directory you specified with --prefix option.

Cleanup

Last thing you can do now is to remove downloaded files. You won't need them now. It's not mandatory, but it's nice to keep server clean.

cd ..
rm -rf 1.6.3.tar.gz 1.6.1.tar.gz 2.4.33.tar.gz apr-1.6.3 apr-util-1.6.1 httpd-2.4.33

Add Apache executables to PATH

If you try to type httpd -v in your command line, it will result in command not found. That's because httpd is not on your $PATH. I'd like to have all executables from Apache available from everywhere. In order to achieve that, create file

sudo vi /etc/profile.d/httpd.sh

and paste there following contents:

pathmunge /usr/local/apache2/bin

Save the file, log out and log in from your current session to reload your profile. After that you should be able to use httpd -v command:)

Add Systemd entry

Starting, restarting, and enabling Apache on server start via systemctl command is very important thing. You need to create another file:

sudo vi /etc/systemd/system/httpd.service

and paste there following contents:

[Unit]
Description=The Apache HTTP Server
After=network.target

[Service]
Type=forking
ExecStart=/usr/local/apache2/bin/apachectl -k start
ExecReload=/usr/local/apache2/bin/apachectl -k graceful
ExecStop=/usr/local/apache2/bin/apachectl -k graceful-stop
PIDFile=/usr/local/apache2/logs/httpd.pid
PrivateTmp=true

[Install]
WantedBy=multi-user.target

Save the file and reload the systemctl daemon

sudo systemctl daemon-reload

Now you can try to start your Apache httpd server with following command:

sudo systemctl start httpd

It should start properly. If you will have any warnings, don't bother with them now. I will show you proper configuration in next step.

Once it's up and running you can try to type your server IP address in your browser like http://43.184.89.190/ and check if you see It works! message:) If so, you have Apache httpd running fine!

Create dedicated user and group for Apache

I usually create additional user and group for httpd daemon. It's good practice from security side. Each service should operate as separate user. It limits possible damage during attacks, httpd exploitation etc.

If you want to learn more about creating user and groups I recommend reading this tutorial. Here I'll just simply create group and user without shell.

sudo groupadd www
sudo useradd httpd -g www --no-create-home --shell /sbin/nologin

You can change the names as you wish. I like to use www group instead of httpd group for example. I usually add there other services as well, like nginx or php-fpm.

Adjust main config file httpd.conf

httpd.conf is main Apache httpd configuration file. You should start by editing this file with editor of your choice. I like to use vi, but you can use nano etc...:

sudo vi /usr/local/apache2/conf/httpd.conf

I usually don't remove any of the configuration directives from that file. If something needs to be deleted I comment it out with # at the beginning of new line. It's easier to revert changes.

Now I scroll through the file from top to bottom looking for particular lines and check if it has correct value. If I don't find given line I just add it usually at the bottom of the file.

Here are the important values:

# Make sure that ServerRoot is set to the same value as --prefix during ./configure
ServerRoot /usr/local/apache2

# Set ServerName to prevent warning on Apache start
ServerName localhost

# Default port set to 80 - HTTP protocol
Listen 80

# Set user and group
User httpd
Group www

# Configure entry file for your application. If you plan to use PHP make sure that it's as first possible file
DirectoryIndex index.php index.html

# Hide Apache version from header and from error files
ServerTokens prod
ServerSignature off

# Disable ETag to prevent disposing sensitive values like iNode
FileETag none

Save the file. After each change to configuration file you must restart HTTPD in order to apply changes. In order to do so execute following command:

sudo systemctl restart httpd

After restarting, make sure that Apache is working fine!

Configure loaded modules

During compilation we set --enable-so modules which means that we can disable and enable modules in configuration files.

List of modules is pretty long. Some of the are disabled (they have # at the beginning of the line). You should know, that the more modules are enabled the "slower" Apache httpd is. I'm not saying that it's super slow, but you can google for some benchmarks showing different configurations.

Here is what I like to do. First of all, I comment out all modules = everything is disabled. I enable only that modules that I really use + the modules that are required for proper functioning of Apache httpd. It has few benefits - Apache is faster, eats less resources (CPU and RAM) and it's more resistant for given attacks. Usually when new security issue pops out, it's rather connected to one of the modules, than whole httpd. So you can have more chances to avoid potential security risk with having some stuff disabled.

So edit main configuration file one more time:

sudo vi /usr/local/apache2/conf/httpd.conf

And set modules that you use. Here is my go-to list of enabled modules:

# These modules must be enabled if you want Apache to start
LoadModule authz_core_module modules/mod_authz_core.so
LoadModule mime_module modules/mod_mime.so
LoadModule log_config_module modules/mod_log_config.so
LoadModule unixd_module modules/mod_unixd.so
LoadModule dir_module modules/mod_dir.so

# If you are using PHP with PHP-FPM which I highly suggest enable proxy modules 
LoadModule proxy_module modules/mod_proxy.so 
LoadModule proxy_fcgi_module modules/mod_proxy_fcgi.so 

# Enable pretty links and mod_rewrite that is highly used in all frameworks and CMSes 
LoadModule rewrite_module modules/mod_rewrite.so 

# Useful for WordPress sites - enables Require for setting up access to given resources. 
LoadModule access_compat_module modules/mod_access_compat.so 

# One more useful thing for WordPress and Let's Encrypt - enables Alias. If you are using composer and wpackagist it's a must, otherwise if you don't plan to use aliases, leave that disabled 
LoadModule alias_module modules/mod_alias.so 

# Enable gzip extension for compressing static files 
LoadModule deflate_module modules/mod_deflate.so 
LoadModule filter_module modules/mod_filter.so 

# Enable expires header for caching assets on browser side 
LoadModule expires_module modules/mod_expires.so 

# Enable SSL 
LoadModule http2_module modules/mod_http2.so 
LoadModule socache_shmcb_module modules/mod_socache_shmcb.so 
LoadModule ssl_module modules/mod_ssl.so 

# Enable status module for monitoring Apache. If you don't plan to use that, leave that commented out 
LoadModule authz_host_module modules/mod_authz_host.so 
LoadModule status_module modules/mod_status.so

Save the changes and restart Apache. Make sure that it works after changes!

Configure MPM

Configure Multi-Processing modules contains two parts. First I override default Apache configuration for event mode that I picked during compilation. In that case you will know what is actually configured. So let's start with that first.

At the bottom of httpd.conf you need to uncomment the line:

Include conf/extra/httpd-mpm.conf

It will enable advanced Apache httpd MPM configuration and it will override the defaults.

Now edit enabled file:

sudo vi /usr/local/apache2/conf/extra/httpd-mpm.conf

This file contains configuration of all MPM There are configuration for each MPM module, so make sure that you are setting correct values. I enabled event mode, so this is the section I care about:

<IfModule mpm_event_module>
    StartServers 5
    MinSpareThreads 75
    MaxSpareThreads 250
    ThreadsPerChild 25
    MaxRequestWorkers 400
    MaxConnectionsPerChild 0
</IfModule>

Save the file and restart Apache. This was the easiest part of MPM configuration.

The real part of MPM configuration is later on when you start running your production website. When you feel that your website/application start running low on higher traffic you can start playing around with that values.

Important thing that you need to know - there is no one config to rule them all. What I want to say is that one config that works fine on one server might not work as fine as on second server. There are dozens of factors like application specific, CPU and RAM, traffic etc. I encourage you to play around with these values to find the optimal settings for your server.

Here is great post that explains in depth MPM configuration. I have two advice's about performance tuning.

First one, that you probably don't even need to change anything if you have regular website without huge amount of traffic. It's just good to know what settings are applied by mpm configuration. When httpd-mpm.conf file was commented out, you didn't have any idea what the settings are. Once it's enabled, you at least know what is configured.

Second advice is - do it slowly. Performance tuning is lengthy process, and as I said, it highly depends on various factors. I like to change one settings, like StartServers for instance and I wait day or two and monitor response times, CPU and RAM usage etc. Sometimes even if you increase something you won't see a difference in response time, but you will get higher CPU usage. Then you just can rollback the changes. If you modify 3 or 4 values at one time, it's hard to say which comes with best (or any) result.

Setup GZIP compression

Using GZIP compression has serious impact on performance and your website loading time. Let's turn it on in few simple steps. In order to use it make sure that mod_deflate and mod_filter are enabled.

First create new file that will contain GZIP settings for Apache:

sudo vi /usr/local/apache2/conf/extra/httpd-deflate.conf

Paste there following content and save the file:

<IfModule mod_deflate.c>
    <IfModule mod_filter.c>
        AddOutputFilterByType DEFLATE application/ecmascript
        AddOutputFilterByType DEFLATE application/javascript
        AddOutputFilterByType DEFLATE application/rss+xml
        AddOutputFilterByType DEFLATE application/xml
        AddOutputFilterByType DEFLATE application/x-javascript
        AddOutputFilterByType DEFLATE text/css
        AddOutputFilterByType DEFLATE text/html
        AddOutputFilterByType DEFLATE text/plain
        AddOutputFilterByType DEFLATE text/xml
    </IfModule>
</IfModule>

It will add GZIP compression to most popular file types such as HTML, CSS, JS etc. If you need anything else that requires compressing, simply add more MIME types.

Once you save the file you need to include it to main Apache configuration. So open httpd.conf one more time and on the bottom of the page there is section where you include different things, such as MPM. In this section add following line:

Include conf/extra/httpd-deflate.conf

Save changes and restart HTTPD. Gzip compression will be enabled!

Setup assets caching with expires headers

Another important thing that has serious impact on performance is caching. If you want to use cache headers make sure that you enabled mod_expires for that purpose. Rest of procedure is similar to enabling GZIP compression.

Start with creating file that will contain configuration for caching:

sudo vi /usr/local/apache2/conf/extra/httpd-expires.conf

Paste following configuration and add/remove mime types or adjust time of expiration it if you need:

<IfModule mod_expires.c>
    # Enable expirations
    ExpiresActive On

    # Expirations for given mime type
    ExpiresByType image/gif "access plus 1 month"
    ExpiresByType image/ico "access plus 1 month"
    ExpiresByType image/jpg "access plus 1 month"
    ExpiresByType image/jpeg "access plus 1 month"
    ExpiresByType image/png "access plus 1 month"
    ExpiresByType text/css "access plus 1 month"
    ExpiresByType text/javascript "access plus 1 month"
</IfModule>

Same as before, you need to add entry to httpd.conf file and after that, restart the server:

Include conf/extra/httpd-expires.conf

Enable SSL configuration

If you plan to use HTTPS which I highly recommend you need to include SSL configuration. By default it is commented out from main configuration file. Before including this file, let's edit it first:

sudo vi /usr/local/apache2/conf/extra/httpd-ssl.conf

File contains secure configuration and sensible defaults that you don't need to change. It will provide secure connection that targets most browsers. However this file also contains default VirtualHost for HTTPS which I always remove. The reason is - I like to know what entry points to the server are available. Since this page doesn't display anything useful we can simply remove it.

So scroll to the point where VirtualHost section starts and remove whole section. It's pretty long so make sure that you remove it completely including <VirutalHost...></VirtualHost> lines :

## Remove this part:
##
## SSL Virtual Host Context
##
<VirtualHost _default_:443>
#...
</VirtualHost>

Save changes to the file. Now it's time to include this file into httpd.conf file. Edit it and scroll to the bottom. SSL is commented out by default so all you need to do is to uncomment it like so:

# Secure (SSL/TLS) connections
Include conf/extra/httpd-ssl.conf

Save the changes and restart HTTPD service. This is only initial part of adding HTTPS to your website. To be able to successfully connect to your server with SSL there are few more steps.

Add Let's Encrypt integration

If you are not using Let's Encrypt free SSL certificates you can skip that part.

When you install certbot for obtaining Let's Encrypt certificates you must somehow validate the domain. I use webroot as authenticator. It means that inside your website directory certbot will create .well-known directory and will try to put some files there. It works in most cases unless you start playing around with root path to your website, like placing it in subdirectory. Sometimes there is also permission issue.

There is neat trick to solve all this issues. When you create new certificate, point webroot to /var/lib/letsencrypt
directory instead to your domain directory like /var/www/blacksaildivision.com/htdocs

Next, create new file for Apache configuration:

sudo vi /usr/local/apache2/conf/extra/httpd-acme.conf

and paste there following contents:

Alias /.well-known/acme-challenge/ "/var/lib/letsencrypt/.well-known/acme-challenge/"
<Directory "/var/lib/letsencrypt/">
    AllowOverride None
    Options MultiViews Indexes SymLinksIfOwnerMatch IncludesNoExec
    Require method GET POST OPTIONS
</Directory>

Please note that mod_alias must be enabled. What it will do on each request to .well-known/acme-challenge that certbot uses it will point it to /var/lib/letsencrypt directory. It solves the problem for all domains globally.

Last thing is to enable this feature in main configuration of Apache. Edit the file and add following section near the bottom of the file where all other Includes are placed:

# Let's Encrypt integration
Include conf/extra/httpd-acme.conf

Restart the Apache to apply new changes.

Enable extended status

If you want to get more insights about Apache or you plan to use monitoring tools like Datadog it's wise to enable extended version of status. It will give you basic info about workers and httpd itself. In order to enable, edit main configuration file and somewhere and following code (I like to place it just before all Include sections):

# Enable extended status
<IfModule status_module>
    ExtendedStatus On
</IfModule>

Remember that you need to enable mod_status and mod_authz_host in order to get status working. Mod_authz_host will be required later on when I show you how to configure localhost. Mod_status response should be restricted to avoid exposing sensible information.

In order to apply changes, please restart httpd.

Setting up root directory

Let's start with final part - setting up Virtual Hosts. There are couple of approaches. It depends how many websites you plan to have on single server, does all your apps have domains or are they just microservices etc. I'll show you two of my approaches. Regardless of any approach you need a directory where you will store you app/website files and logs.

On CentOS there should be directory /var/www which is recommended place to store website files. If you don't have such directory create one first:

sudo mkdir /var/www

Make sure that this directory has valid permission and valid owner which should be root:

sudo chmod 755 /var/www
sudo chown root:root /var/www

Setting up website directories for files and logs

Once root directory is ready it's time to setup directories for websites. Let's assume that I want to create folder structure for blacksaildivision.com website. So first I create directory inside /var/www and name it as domain:

sudo mkdir /var/www/blacksaildivision.com

Inside this directory I need two separate directories. One for my website files like index.html etc and one for logs. There are many ways of keeping logs on the server. Some people uses native directories like /usr/local/apache2/logs or /var/log but I prefer to keep everything in one place. So all nginx/httpd/php logs will go to logs directory inside my domain directory.

sudo mkdir /var/www/blacksaildivision.com/htdocs
sudo mkdir /var/www/blacksaildivision.com/logs

Once directories are created it's time to set valid owner and permissions. Let's start with ownership:

sudo chown root:root /var/www/blacksaildivision.com
sudo chown developer:www /var/www/blacksaildivision.com/htdocs
sudo chown developer:www /var/www/blacksaildivision.com/logs

So main directory for domain should be owned by root. However two directories inside should be owned by custom user. In that case main user for the server is called developer. He has sudo powers and has access to website files and can perform commands like git pull to download latest code.

Why not httpd user that we created for Apache? The reasons are permissions. When you download files with git pull as developer user, but directory is owned by httpd user it most often leads to unexpected errors and mismatch in owners.

If you need ( and you should ) create separate account for developer/server owner read this tutorial.

Group is set to www which I usually use as generic group for all website related applications such as httpd, php-fpm etc. Please note that developer user also belongs to that group.

Now it's time to set directory permissions:

sudo chmod 755 /var/www/blacksaildivision.com
sudo chmod 2775 /var/www/blacksaildivision.com/htdocs
sudo chmod 2775 /var/www/blacksaildivision.com/logs

2 at the beginning means that every new subdirectory created will have the same ownership as parent directory (developer:www)

So what if I need to store more than one domain? Simply create new directory inside /var/www like mywebsite.com and repeat the steps with htdocs, logs directory, set ownership and permissions.

Do I need to create domain directory? It depends. I usually create such directory even if I host single website only. There are some cases like microservices that does not have a domain and are run behind load-balancer. In that case you can skip creating domain directory and use /var/www/htdocs and /var/www/logs. Just remember to change paths accordingly in next steps.

Create basic Virtual Host file for HTTP website

Directories were created so now it's the most important part - setting up VirtualHost. Again, there are many different approaches how to store the virtual hosts etc. I'll show you mine. Let's create basic Virtual Host file that will only load static files from given domain. As example I use blacksaildivision.com domain.

First I create a file that will contain configuration for HTTP version of the website. I always add domain to the filename so it's easier to find given configuration if you have multiple domains:

sudo vi /usr/local/apache2/conf/extra/httpd-vhost-blacksaildivision.com.conf

Paste Virtual Host config there and adjust your domain and directory structure:

<VirtualHost *:80>

ServerName blacksaildivision.com

# Directory settings
DocumentRoot /var/www/blacksaildivision.com/htdocs
<Directory /var/www/blacksaildivision.com/htdocs>
    AllowOverride All
    Require all granted
    Options +FollowSymLinks -Indexes -Includes
</Directory>

# Logging
ErrorLog "/var/www/blacksaildivision.com/logs/httpd-error.log"
CustomLog "/var/www/blacksaildivision.com/logs/httpd-access.log" common

</VirtualHost>

File starts and ends with block defining VirtualHost. Inside this blocks you need to place your domain configuration. First one is ServerName which is your domain.

Next part is directory settings. You need to point httpd to read files from correct directory which is defined by DocumentRoot. Just below that line there are settings for root directory. AllowOverride will allow .htaccess files to override all default instructions in this block. Require all granted adds general access to this directory. It's a must if you want to read files from given location. Lastly I allow following symlinks which are often used by various frameworks and CMSes. I disable Indexes and Includes because of security reasons.

Last parts are logs. I define two logs. One is error log which will contain all invalid requests details etc. CustomLog is simply access log that will contain all requests.

So in general if you want to add different or another domain, simply create file with configuration like above and update ServerName, DocumentRoot and paths to logs.

Last part is to include this configuration file in main httpd configuration file:

sudo vi /usr/local/apache2/conf/httpd.conf

and at the very bottom of the file Include configuration:

Include conf/extra/httpd-vhost-blacksaildivision.conf

Save changes and restart Apache. Now try to visit your website! In case of any issues like 4xx/5xx errors simply check error log and see what the problem is. Usually there are typos or incorrect configuration of your domain causing the issues.

Adding PHP support

Most of you will probably use Apache with PHP. I use PHP in PHP-FPM mode. In my opinion it gives greater control over mod_php when it comes to performance tuning, configuration etc. It also has one more benefit - if you will ever need to switch from Apache to Nginx it's much easier as preferred way of using nginx + php is PHP-FPM.

If you want to read more about how to install and configure PHP - please follow this tutorial.

Edit the VirtualHost file where you want to add PHP support and start adding there following lines ( I prefer to add it just before logs section):

# PHP-FPM settings
<Proxy "fcgi://127.0.0.1:9001" timeout=30>
</Proxy>

It will define Proxy for PHP-FPM daemon. In my case FPM process is running on localhost (127.0.0.1) and on port 9001. Optional parameter is timeout. It's not required but sometimes it's helpful. Imagine situation where one of your scripts has bug like infinite loop or it's execution time takes way more than 30s. Apache will have to wait until proxy will return something. Now imagine that someone called this script 10000 times. It will kill your httpd daemon. It's safe to add timeout as additional guard. You can experiment with timeoutvalue for your application.

Proxy is defined, not it's time to use it. Just after section add following lines:

<FilesMatch "\.php$">
    <If "-f %{SCRIPT_FILENAME}">
        SetHandler "proxy:fcgi://127.0.0.1:9001"
    </If>
</FilesMatch>

First I use FilesMatch to detect if requested file has .php extension. If it has I'm checking if the file actually exists. If you won't check it, request will be passed to FPM process anyway which can result in unexpected results and unnecessary lines in log files.

If everything is OK I'm setting Handler to defined proxy and PHP will handle rest of the request.

You can save the file and restart Apache and check if everything works fine:)

If you are using status or ping from PHP-FPM for performance debugging or tools such as Datadog and you don't want to expose additional port in your firewall, you can achieve it with HTTPD as well. Simply add following lines before <FilesMatch> section:

<LocationMatch "/(status|ping)">
    RewriteEngine Off
    Require all denied
    Require ip 127.0.0.1 60.120.72.81
    SetHandler "proxy:fcgi://127.0.0.1:9001"
</LocationMatch>

I'm checking if requested path matches /status or /ping. If match is found I'm turning of RewriteEngine in case of redirect in .htaccess etc. Than I'm turning off access for everyone but I allow access from list of IPs. I allow access from localhost, but I also allow access from my server IP address. So for instance If my server has IP 60.120.72.81 I add it as well.

Last thing is to set handler to use to proxy for PHP-FPM daemon.

Enable HTTPS inside VirtualHost

It's time to enable HTTPS for our website! I assume that you already have SSL certificates purchased and downloaded or generated via Let's Encrypt.

Edit the file first:

sudo vi /usr/local/apache2/conf/extra/httpd-vhost-blacksaildivision.com.conf

Just for now you can leave the regular HTTP version and add following contents below VirtualHost section. In such way you will have both HTTP and HTTPS enabled for single website. Later on I'll show you how to redirect HTTP to HTTPS. So just paste the following contents at the end of edited file:

<IfModule mod_ssl.c>
<VirtualHost *:443>

ServerName blacksaildivision.com
ServerAlias www.blacksaildivision.com

# Redirect www to non-www
RedirectMatch permanent "^www\.(.*)$" "https://blacksaildivision.com/"

# Directory settings
DocumentRoot /var/www/blacksaildivision.com/htdocs
<Directory /var/www/blacksaildivision.com/htdocs>
    AllowOverride All
    Require all granted
    Options +FollowSymLinks -Indexes -Includes
</Directory>

# PHP-FPM settings
<Proxy "fcgi://127.0.0.1:9001" timeout=30>
</Proxy>

<LocationMatch "/(status|ping)">
    RewriteEngine Off
    Require all denied
    Require ip 127.0.0.1
    SetHandler "proxy:fcgi://127.0.0.1:9001"
</LocationMatch>

<FilesMatch "\.php$">
    <If "-f %{SCRIPT_FILENAME}">
        SetHandler "proxy:fcgi://127.0.0.1:9001"
    </If>
</FilesMatch>

# Logging
ErrorLog "/var/www/blacksaildivision.com/logs/httpd-error.log"
CustomLog "/var/www/blacksaildivision.com/logs/httpd-access.log" common

# SSL configuration
SSLEngine on
SSLCertificateFile "/etc/letsencrypt/live/blacksaildivision.com/cert.pem"
SSLCertificateKeyFile "/etc/letsencrypt/live/blacksaildivision.com/privkey.pem"
SSLCertificateChainFile "/etc/letsencrypt/live/blacksaildivision.com/chain.pem"

</VirtualHost>
</IfModule>

Everything is wrapped with IfModule section. I usually check if mod_ssl is enabled. In case someone by accident would remove that module from list of enabled modules, section with VirutalHost simply won't be loaded and will not throw an error.

This is new VirtualHost so it must be wrapped in <VirtualHost *:443> section. Please note that port is now set to 443 instead of 80. It's default port for HTTPS. You might see some similarities between HTTP and HTTPS version. Most of things are just copied from HTTP version, so I won't be covering this parts here. Instead I will focus on new things.

You already know ServerName directive. But below there is another one - ServerAlias. You can basically access your website in two ways - with www. (https://www.blacksaildivision.com) and without www. (https://blacksaildivision.com). I prefer to use version without www. Less typing and URL looks more friendly IMHO:) So I want to redirect all www traffic to non-www. We don't have such redirect in HTTP version, but we will add it later on when I'll show you how to redirect from HTTP to HTTPS.

ServerAlias create an alias to given VirtualHost identified by ServerName. So no matter which URL you will use - the one from ServerName or from ServerAlias(es), Apache will use configuration from given VirtualHost. For instance we can add another alias like - ServerAlias blacksaildivisioncopy.com and it can point to same configuration. So your website can be accessible from two different URLs. It's very rare case but this is just an example.

What is important that your website should have redirect, so there always will be only single copy of your website. For instance if you have both www and non-www versions available without any redirect, your content will be indexed twice and will be seen as two different websites. It's bad for the SEO and your ranking in search engines. In order to redirect from non-www to www you should use RedirectMatch directive. This is permanent redirect, so it won't (and should not) change in the future. Also please make sure that you have your SSL cert valid for www. domain as well. If you won't have it, you will get an error when visiting version with www. prefix.

Last new part is SSL configuration at the bottom of the file. First we need to tell Apache that we will use SSL with SSLEngine on. Next are the paths to Certificate, Key and Chain. Chain is sometimes not mandatory in some SSL providers. So if you don't have Chain file, skip this directive. I'm using Let's Encrypt so paths to SSL are set to /etc/letsencrypt/live/blacksaildivision.com/ If you just have certificates bought from SSL provider, simply create new directory inside your domain like so:

sudo mkdir /var/www/blacksaildivision.com/ssl

and place all cert files inside this directory. Remember to update paths inside your VirtualHosts!

Once it's done simply save the changes and restart Apache. Try to visit your website with HTTPS and HTTP. Both version should work just fine. You can also check your server with https://www.ssllabs.com/ssltest/ If you configured everything correctly, you should get A score. You can aim for A+, but in my opinion there is too much disadvantages like limited access to your website from older devices etc.

Redirect HTTP to HTTPS

As we want to serve traffic over HTTPS only, we need to redirect all HTTP requests to HTTPS. Edit the file with your domain configuration and replace <VirtualHost *:80> to following code:

<VirtualHost *:80>

ServerName blacksaildivision.com
ServerAlias www.blacksaildivision.com

# Redirect everything permanently to https://blacksaildivision.com/
Redirect permanent "/" "https://blacksaildivision.com/"

# Turn off logging
ErrorLog /dev/null
CustomLog /dev/null common

</VirtualHost>

It's much shorter than previous version. I added ServerAlias with www. prefix. Using Redirect directive I'm redirecting all traffic to https:// version. And last thing is turning off logging. It's not necessary to log redirects from HTTP to HTTPS. If you have logging in HTTPS VirutalHost, logs will be there anyway. There's no need to duplicate code.

Save changes, restart Apache and check if redirect is working fine:)

Run Apache httpd on system start

Last thing is to add Apache httpd daemon to start with system boot. So after server start/restart httpd will run automatically:

sudo systemctl enable httpd

So that's it. You have fully working Apache httpd in latest version installed on your system 🙂 This process might take some time, but you will have full control over httpd.

As always you can use our LampOnSteroids project (based on Ansible) to speed and automate everything up!

How to install EPEL repository on CentOS

3 Replies

We need to install EPEL repository for our CentOS. This will be first step to setup our working Web Server. EPEL is additional repository for yum, with tons of useful packages which we won't find in default base repository. We will use it in the future so let's start using it now;)

In this post we will also setup local vagrant box. We will be using it for future operations like installing Apache or Varnish.

[sc:lamp_series]

Vagrant setup

The best idea without messing everything out is to use Vagrant.

If You don't have Vagrant installed please download and install it first. After installation You should be ready to use Vagrant. Create directory in place where You want to keep Your vagrant file.

mkdir vms
cd vms

Next thing what we need to do is to download CentOS box. We need the box to replace default one that comes with Vagrant. We will use chef/centos-6.6 from Vagrant boxes directory. You can search more boxes here if You want, for instance You can use 6.5 instead of 6.6. Decision is Yours:)

vagrant box add chef/centos-6.6

Vagrant will download the image of OS You selected. It might take a while, depending on Your network performance.

Next we need to init Vagrant instance.

vagrant init chef/centos-6.6

It will create Vagrantfile in Your directory. You can check out this file in any editor. This file has basic Vagrant configuration, you can adjust the options like forwarded ports, synced folders etc. For now, let's leave this configuration file and let's bring our machine to life!

vagrant up

It will init the machine. After that You can login via SSH and start playing around:)

vagrant ssh

tl;dr

mkdir vms
cd vms
vagrant init chef/centos-6.6
vagrant up
vagrant ssh

How to install EPEL

Installing EPEL on CentOS is really easy. First of all You need to get the URL for EPEL repo. If You are just following the instructions in this tutorial You can execute the command. But for instance if You have 32bit version instead of 64bit You need to replace x86_64 to i386

yum install http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm

Depending on Your vagrant / server setup You might need to execute this command as root or at least as sudo user. If You are just following the steps in this tutorial You are probably Vagrant user. If You execute this command You will see permission denied error. Start this command with sudo (sudo yum install http://....) and everything should be OK:)

Next thing that we need to do is to import GPG key for this repo:

rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

And basically that's it! You are now able to use EPEL packages with yum!

To validate the installation You can execute yum repolist command and You should see epel Extra Packages for Enterprise Linux 6 - x86_64

yum repolist

It means that everything is OK. Now, if You want to install any packages with the EPEL repository You need to use

yum --enablerepo=epel install PACKAGE_NAME

tl;dr

yum install http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rp -y
rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6

Using Ansible to install EPEL

If You are using Ansible for server provisioning as I do, You can find ansible-webserver project on GitHub

https://github.com/astaz3l/ansible-webserver

It has EPEL role, that will help You install EPEL via Ansible