apache web server

(Written by Paul Cobbaut, https://github.com/paulcobbaut/, with contributions by: Hans Roes, https://github.com/Blokker-1999/, Alex M. Schapelle, https://github.com/zero-pytagoras/)

In this chapter we learn how to setup a web server with the apache software.

According to NetCraft (http://news.netcraft.com/archives/web_server_survey.html) about seventy percent of all web servers are running on Apache. The name is derived from a patchy web server, because of all the patches people wrote for the NCSA httpd server.

Later chapters will expand this web server into a LAMP stack (Linux, Apache, Mysql, Perl/PHP/Python).

introduction to apache

installing on Debian

This screenshot shows that there is no apache server installed, nor does the /var/www directory exist.

root@linux:~# ls -l /var/www
ls: cannot access /var/www: No such file or directory
root@linux:~# dpkg -l | grep apache

To install apache on Debian:

root@linux:~# aptitude install apache2
The following NEW packages will be installed:
  apache2 apache2-mpm-worker{a} apache2-utils{a} apache2.2-bin{a} apache2.2-com\
mon{a} libapr1{a} libaprutil1{a} libaprutil1-dbd-sqlite3{a} libaprutil1-ldap{a}\
 ssl-cert{a} 
0 packages upgraded, 10 newly installed, 0 to remove and 0 not upgraded.
Need to get 1,487 kB of archives. After unpacking 5,673 kB will be used.
Do you want to continue? [Y/n/?]

After installation, the same two commands as above will yield a different result:

root@linux:~# ls -l /var/www
total 4
-rw-r--r-- 1 root root 177 Apr 29 11:55 index.html
root@linux:~# dpkg -l | grep apache | tr -s ' '
ii apache2 2.2.22-13+deb7u1 amd64 Apache HTTP Server metapackage
ii apache2-mpm-worker 2.2.22-13+deb7u1 amd64 Apache HTTP Server - high speed th\
readed model
ii apache2-utils 2.2.22-13+deb7u1 amd64 utility programs for webservers
ii apache2.2-bin 2.2.22-13+deb7u1 amd64 Apache HTTP Server common binary files
ii apache2.2-common 2.2.22-13+deb7u1 amd64 Apache HTTP Server common files

installing on RHEL/CentOS

Note that Red Hat derived distributions use httpd as package and process name instead of apache.

To verify whether apache is installed in CentOS/RHEL:

[root@linux ~]# rpm -q httpd
package httpd is not installed
[root@linux ~]# ls -l /var/www
ls: cannot access /var/www: No such file or directory

To install apache on CentOS:

[root@linux ~]# yum install httpd

After running the yum install httpd command, the Centos 6.5 server has apache installed and the /var/www directory exists.

[root@linux ~]# rpm -q httpd
httpd-2.2.15-30.el6.centos.x86_64
[root@linux ~]# ls -l /var/www
total 16
drwxr-xr-x. 2 root root 4096 Apr  3 23:57 cgi-bin
drwxr-xr-x. 3 root root 4096 May  6 13:08 error
drwxr-xr-x. 2 root root 4096 Apr  3 23:57 html
drwxr-xr-x. 3 root root 4096 May  6 13:08 icons
[root@linux ~]#

running apache on Debian

This is how you start apache2 on Debian.

root@linux:~# service apache2 status
Apache2 is NOT running.
root@linux:~# service apache2 start
Starting web server: apache2apache2: Could not reliably determine the server's \
fully qualified domain name, using 127.0.1.1 for ServerName
.

To verify, run the service apache2 status command again or use ps.

root@linux:~# service apache2 status
Apache2 is running (pid 3680).
root@linux:~# ps -C apache2
  PID TTY          TIME CMD
 3680 ?        00:00:00 apache2
 3683 ?        00:00:00 apache2
 3684 ?        00:00:00 apache2
 3685 ?        00:00:00 apache2
root@linux:~#

Or use wget and file to verify that your web server serves an html document.

root@linux:~# wget 127.0.0.1
--2014-05-06 13:27:02--  http://127.0.0.1/
Connecting to 127.0.0.1:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 177 [text/html]
Saving to: `index.html'

100%[==================================================>] 177    --.-K/s   in 0s

2014-05-06 13:27:02 (15.8 MB/s) - `index.html' saved [177/177]

root@linux:~# file index.html
index.html: HTML document, ASCII text
root@linux:~#

Or verify that apache is running by opening a web browser, and browse to the ip-address of your server. An Apache test page should be shown.

You can do the following to quickly avoid the \'could not reliably determine the fqdn\' message when restarting apache.

root@linux:~# echo ServerName debian10 >> /etc/apache2/apache2.conf
root@linux:~# service apache2 restart
Restarting web server: apache2 ... waiting .
root@linux:~#

running apache on CentOS

Starting the httpd on RHEL/CentOS is done with the service command.

[root@linux ~]# service httpd status
httpd is stopped
[root@linux ~]# service httpd start
Starting httpd: httpd: Could not reliably determine the server's fully qualifie\
d domain name, using 127.0.0.1 for ServerName
                                                           [  OK  ]
[root@linux ~]#

To verify that apache is running, use ps or issue the service httpd status command again.

[root@linux ~]# service httpd status
httpd (pid  2410) is running...
[root@linux ~]# ps -C httpd
  PID TTY          TIME CMD
 2410 ?        00:00:00 httpd
 2412 ?        00:00:00 httpd
 2413 ?        00:00:00 httpd
 2414 ?        00:00:00 httpd
 2415 ?        00:00:00 httpd
 2416 ?        00:00:00 httpd
 2417 ?        00:00:00 httpd
 2418 ?        00:00:00 httpd
 2419 ?        00:00:00 httpd
[root@linux ~]#

To prevent the \'Could not reliably determine the fqdn\' message, issue the following command.

[root@linux ~]# echo ServerName Centos65 >> /etc/httpd/conf/httpd.conf
[root@linux ~]# service httpd restart
Stopping httpd:                                            [  OK  ]
Starting httpd:                                            [  OK  ]
[root@linux ~]#

index file on CentOS

CentOS does not provide a standard index.html or index.php file. A simple wget gives an error.

[root@linux ~]# wget 127.0.0.1
--2014-05-06 15:10:22--  http://127.0.0.1/
Connecting to 127.0.0.1:80... connected.
HTTP request sent, awaiting response... 403 Forbidden
2014-05-06 15:10:22 ERROR 403: Forbidden.

Instead when visiting the ip-address of your server in a web browser you get a noindex.html page. You can verify this using wget.

[root@linux ~]# wget http://127.0.0.1/error/noindex.html
--2014-05-06 15:16:05--  http://127.0.0.1/error/noindex.html
Connecting to 127.0.0.1:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 5039 (4.9K) [text/html]
Saving to: “noindex.html”

100%[=============================================>] 5,039       --.-K/s   in 0s

2014-05-06 15:16:05 (289 MB/s) - “noindex.html” saved [5039/5039]

[root@linux ~]# file noindex.html
noindex.html: HTML document text
[root@linux ~]#

Any custom index.html file in /var/www/html will immediately serve as an index for this web server.

[root@linux ~]# echo 'Welcome to my website' > /var/www/html/index.html
[root@linux ~]# wget http://127.0.0.1
--2014-05-06 15:19:16--  http://127.0.0.1/
Connecting to 127.0.0.1:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 22 [text/html]
Saving to: “index.html”

100%[=============================================>] 22          --.-K/s   in 0s

2014-05-06 15:19:16 (1.95 MB/s) - “index.html” saved [22/22]

[root@linux ~]# cat index.html
Welcome to my website

default website

Changing the default website of a freshly installed apache web server is easy. All you need to do is create (or change) an index.html file in the DocumentRoot directory.

To locate the DocumentRoot directory on Debian:

root@linux:~# grep DocumentRoot /etc/apache2/sites-available/default
        DocumentRoot /var/www

This means that /var/www/index.html is the default web site.

root@linux:~# cat /var/www/index.html
<html><body><h1>It works!</h1>
<p>This is the default web page for this server.</p>
<p>The web server software is running but no content has been added, yet.</p>
</body></html>
root@linux:~#

This screenshot shows how to locate the DocumentRoot directory on RHEL/CentOS.

[root@linux ~]# grep ^DocumentRoot /etc/httpd/conf/httpd.conf
DocumentRoot "/var/www/html"

RHEL/CentOS have no default web page (only the noindex.html error page mentioned before). But an index.html file created in /var/www/html/ will automatically be used as default page.

[root@linux ~]# echo '<html><head><title>Default website</title></head><body\
><p>A new web page</p></body></html>' > /var/www/html/index.html
[root@linux ~]# cat /var/www/html/index.html
<html><head><title>Default website</title></head><body><p>A new web page</p></b\
ody></html>
[root@linux ~]#

apache configuration

There are many similarities, but also a couple of differences when configuring apache on Debian or on CentOS. Both Linux families will get their own chapters with examples.

All configuration on RHEL/CentOS is done in /etc/httpd.

[root@linux ~]# ls -l /etc/httpd/
total 8
drwxr-xr-x. 2 root root 4096 May  6 13:08 conf
drwxr-xr-x. 2 root root 4096 May  6 13:08 conf.d
lrwxrwxrwx. 1 root root   19 May  6 13:08 logs -> ../../var/log/httpd
lrwxrwxrwx. 1 root root   29 May  6 13:08 modules -> ../../usr/lib64/httpd/modu\
les
lrwxrwxrwx. 1 root root   19 May  6 13:08 run -> ../../var/run/httpd
[root@linux ~]#

Debian (and ubuntu/mint/...) use /etc/apache2.

root@linux:~# ls -l /etc/apache2/
total 72
-rw-r--r-- 1 root root  9659 May  6 14:23 apache2.conf
drwxr-xr-x 2 root root  4096 May  6 13:19 conf.d
-rw-r--r-- 1 root root  1465 Jan 31 18:35 envvars
-rw-r--r-- 1 root root 31063 Jul 20  2013 magic
drwxr-xr-x 2 root root  4096 May  6 13:19 mods-available
drwxr-xr-x 2 root root  4096 May  6 13:19 mods-enabled
-rw-r--r-- 1 root root   750 Jan 26 12:13 ports.conf
drwxr-xr-x 2 root root  4096 May  6 13:19 sites-available
drwxr-xr-x 2 root root  4096 May  6 13:19 sites-enabled
root@linux:~#

port virtual hosts on Debian

default virtual host

Debian has a virtualhost configuration file for its default website in /etc/apache2/sites-available/default.

root@linux:~# head -2 /etc/apache2/sites-available/default
<VirtualHost *:80>
        ServerAdmin webmaster@localhost

three extra virtual hosts

In this scenario we create three additional websites for three customers that share a clubhouse and want to jointly hire you. They are a model train club named Choo Choo, a chess club named Chess Club 42 and a hackerspace named hunter2.

One way to put three websites on one web server, is to put each website on a different port. This screenshot shows three newly created virtual hosts, one for each customer.

root@linux:~# vi /etc/apache2/sites-available/choochoo
root@linux:~# cat /etc/apache2/sites-available/choochoo
<VirtualHost *:7000>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/choochoo
</VirtualHost>
root@linux:~# vi /etc/apache2/sites-available/chessclub42
root@linux:~# cat /etc/apache2/sites-available/chessclub42
<VirtualHost *:8000>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/chessclub42
</VirtualHost>
root@linux:~# vi /etc/apache2/sites-available/hunter2
root@linux:~# cat /etc/apache2/sites-available/hunter2
<VirtualHost *:9000>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/hunter2
</VirtualHost>

Notice the different port numbers 7000, 8000 and 9000. Notice also that we specified a unique DocumentRoot for each website.

Are you using Ubuntu or Mint, then these configfiles need to end in .conf.

three extra ports

We need to enable these three ports on apache in the ports.conf file. Open this file with vi and add three lines to listen on three extra ports.

root@linux:~# vi /etc/apache2/ports.conf

Verify with grep that the Listen directives are added correctly.

root@linux:~# grep ^Listen /etc/apache2/ports.conf
Listen 80
Listen 7000
Listen 8000
Listen 9000

three extra websites

Next we need to create three DocumentRoot directories.

root@linux:~# mkdir /var/www/choochoo
root@linux:~# mkdir /var/www/chessclub42
root@linux:~# mkdir /var/www/hunter2

And we have to put some really simple website in those directories.

root@linux:~# echo 'Choo Choo model train Choo Choo' > /var/www/choochoo/inde\
x.html
root@linux:~# echo 'Welcome to chess club 42' > /var/www/chessclub42/index.ht\
ml
root@linux:~# echo 'HaCkInG iS fUn At HuNtEr2' > /var/www/hunter2/index.html

enabling extra websites

The last step is to enable the websites with the a2ensite command. This command will create links in sites-enabled.

The links are not there yet...

root@linux:~# cd /etc/apache2/ 
root@linux:/etc/apache2# ls sites-available/ 
chessclub42  choochoo  default  default-ssl  hunter2
root@linux:/etc/apache2# ls sites-enabled/ 
000-default

So we run the a2ensite command for all websites.

root@linux:/etc/apache2# a2ensite choochoo 
Enabling site choochoo.
To activate the new configuration, you need to run:
  service apache2 reload
root@linux:/etc/apache2# a2ensite chessclub42 
Enabling site chessclub42.
To activate the new configuration, you need to run:
  service apache2 reload
root@linux:/etc/apache2# a2ensite hunter2 
Enabling site hunter2.
To activate the new configuration, you need to run:
  service apache2 reload

The links are created, so we can tell apache.

root@linux:/etc/apache2# ls sites-enabled/ 
000-default  chessclub42  choochoo  hunter2
root@linux:/etc/apache2# service apache2 reload 
Reloading web server config: apache2.
root@linux:/etc/apache2#

testing the three websites

Testing the model train club named Choo Choo on port 7000.

root@linux:/etc/apache2# wget 127.0.0.1:7000 
--2014-05-06 21:16:03--  http://127.0.0.1:7000/
Connecting to 127.0.0.1:7000... connected.
HTTP request sent, awaiting response... 200 OK
Length: 32 [text/html]
Saving to: `index.html'

100%[============================================>] 32          --.-K/s   in 0s

2014-05-06 21:16:03 (2.92 MB/s) - `index.html' saved [32/32]

root@linux:/etc/apache2# cat index.html 
Choo Choo model train Choo Choo

Testing the chess club named Chess Club 42 on port 8000.

root@linux:/etc/apache2# wget 127.0.0.1:8000 
--2014-05-06 21:16:20--  http://127.0.0.1:8000/
Connecting to 127.0.0.1:8000... connected.
HTTP request sent, awaiting response... 200 OK
Length: 25 [text/html]
Saving to: `index.html.1'

100%[===========================================>] 25          --.-K/s   in 0s

2014-05-06 21:16:20 (2.16 MB/s) - `index.html.1' saved [25/25]

root@linux:/etc/apache2# cat index.html.1 
Welcome to chess club 42

Testing the hacker club named hunter2 on port 9000.

root@linux:/etc/apache2# wget 127.0.0.1:9000 
--2014-05-06 21:16:30--  http://127.0.0.1:9000/
Connecting to 127.0.0.1:9000... connected.
HTTP request sent, awaiting response... 200 OK
Length: 26 [text/html]
Saving to: `index.html.2'

100%[===========================================>] 26          --.-K/s   in 0s

2014-05-06 21:16:30 (2.01 MB/s) - `index.html.2' saved [26/26]

root@linux:/etc/apache2# cat index.html.2 
HaCkInG iS fUn At HuNtEr2

Cleaning up the temporary files.

root@linux:/etc/apache2# rm index.html index.html.1 index.html.2

Try testing from another computer using the ip-address of your server.

named virtual hosts on Debian

named virtual hosts

The chess club and the model train club find the port numbers too hard to remember. They would prefere to have their website accessible by name.

We continue work on the same server that has three websites on three ports. We need to make sure those websites are accesible using the names choochoo.local, chessclub42.local and hunter2.local.

We start by creating three new virtualhosts.

root@linux:/etc/apache2/sites-available# vi choochoo.local 
root@linux:/etc/apache2/sites-available# vi chessclub42.local 
root@linux:/etc/apache2/sites-available# vi hunter2.local 
root@linux:/etc/apache2/sites-available# cat choochoo.local 
<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        ServerName choochoo.local
        DocumentRoot /var/www/choochoo
</VirtualHost>
root@linux:/etc/apache2/sites-available# cat chessclub42.local 
<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        ServerName chessclub42.local
        DocumentRoot /var/www/chessclub42
</VirtualHost>
root@linux:/etc/apache2/sites-available# cat hunter2.local 
<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        ServerName hunter2.local
        DocumentRoot /var/www/hunter2
</VirtualHost>
root@linux:/etc/apache2/sites-available#

Notice that they all listen on port 80 and have an extra ServerName directive.

name resolution

We need some way to resolve names. This can be done with DNS, which is discussed in another chapter. For this demo it is also possible to quickly add the three names to the /etc/hosts file.

root@linux:/etc/apache2/sites-available# grep ^192 /etc/hosts 
192.168.42.50 choochoo.local
192.168.42.50 chessclub42.local
192.168.42.50 hunter2.local

Note that you may have another ip address...

enabling virtual hosts

Next we enable them with a2ensite.

root@linux:/etc/apache2/sites-available# a2ensite choochoo.local 
Enabling site choochoo.local.
To activate the new configuration, you need to run:
  service apache2 reload
root@linux:/etc/apache2/sites-available# a2ensite chessclub42.local 
Enabling site chessclub42.local.
To activate the new configuration, you need to run:
  service apache2 reload
root@linux:/etc/apache2/sites-available# a2ensite hunter2.local 
Enabling site hunter2.local.
To activate the new configuration, you need to run:
  service apache2 reload

reload and verify

After a service apache2 reload the websites should be available by name.

root@linux:/etc/apache2/sites-available# service apache2 reload
Reloading web server config: apache2.
root@linux:/etc/apache2/sites-available# wget chessclub42.local 
--2014-05-06 21:37:13--  http://chessclub42.local/
Resolving chessclub42.local (chessclub42.local)... 192.168.42.50
Connecting to chessclub42.local (chessclub42.local)|192.168.42.50|:80... conne\
cted.
HTTP request sent, awaiting response... 200 OK
Length: 25 [text/html]
Saving to: `index.html'

100%[=============================================>] 25         --.-K/s   in 0s

2014-05-06 21:37:13 (2.06 MB/s) - `index.html' saved [25/25]

root@linux:/etc/apache2/sites-available# cat index.html 
Welcome to chess club 42

password protected website on Debian

You can secure files and directories in your website with a .htaccess file that refers to a .htpasswd file. The htpasswd command can create a .htpasswd file that contains a userid and an (encrypted) password.

This screenshot creates a user and password for the hacker named cliff and uses the -c flag to create the .htpasswd file.

root@linux:~# htpasswd -c /var/www/.htpasswd cliff 
New password:
Re-type new password:
Adding password for user cliff
root@linux:~# cat /var/www/.htpasswd
cliff:$apr1$vujll0KL$./SZ4w9q0swhX93pQ0PVp.

Hacker rob also wants access, this screenshot shows how to add a second user and password to .htpasswd.

root@linux:~# htpasswd /var/www/.htpasswd rob 
New password:
Re-type new password:
Adding password for user rob
root@linux:~# cat /var/www/.htpasswd 
cliff:$apr1$vujll0KL$./SZ4w9q0swhX93pQ0PVp.
rob:$apr1$HNln1FFt$nRlpF0H.IW11/1DRq4lQo0

Both Cliff and Rob chose the same password (hunter2), but that is not visible in the .htpasswd file because of the different salts.

Next we need to create a .htaccess file in the DocumentRoot of the website we want to protect. This screenshot shows an example.

root@linux:~# cd /var/www/hunter2/ 
root@linux:/var/www/hunter2# cat .htaccess 
AuthUserFile /var/www/.htpasswd
AuthName "Members only!"
AuthType Basic
require valid-user

Note that we are protecting the website on port 9000 that we created earlier.

And because we put the website for the Hackerspace named hunter2 in a subdirectory of the default website, we will need to adjust the AllowOvveride parameter in /etc/apache2/sites-available/default as this screenshot shows (with line numbers on debian10, your may vary).

9         <Directory /var/www/>
10                 Options Indexes FollowSymLinks MultiViews
11                 AllowOverride Authconfig
12                 Order allow,deny
13                 allow from all
14         </Directory

Now restart the apache2 server and test that it works!

port virtual hosts on CentOS

default virtual host

Unlike Debian, CentOS has no virtualHost configuration file for its default website. Instead the default configuration will throw a standard error page when no index file can be found in the default location (/var/www/html).

three extra virtual hosts

In this scenario we create three additional websites for three customers that share a clubhouse and want to jointly hire you. They are a model train club named Choo Choo, a chess club named Chess Club 42 and a hackerspace named hunter2.

One way to put three websites on one web server, is to put each website on a different port. This screenshot shows three newly created virtual hosts, one for each customer.

[root@CentOS65 ~]# vi /etc/httpd/conf.d/choochoo.conf
[root@CentOS65 ~]# cat /etc/httpd/conf.d/choochoo.conf
<VirtualHost *:7000>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/html/choochoo
</VirtualHost>
[root@CentOS65 ~]# vi /etc/httpd/conf.d/chessclub42.conf
[root@CentOS65 ~]# cat /etc/httpd/conf.d/chessclub42.conf
<VirtualHost *:8000>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/html/chessclub42
</VirtualHost>
[root@CentOS65 ~]# vi /etc/httpd/conf.d/hunter2.conf
[root@CentOS65 ~]# cat /etc/httpd/conf.d/hunter2.conf
<VirtualHost *:9000>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/html/hunter2
</VirtualHost>

Notice the different port numbers 7000, 8000 and 9000. Notice also that we specified a unique DocumentRoot for each website.

three extra ports

We need to enable these three ports on apache in the httpd.conf file.

[root@CentOS65 ~]# vi /etc/httpd/conf/httpd.conf
root@linux:~# grep ^Listen /etc/httpd/conf/httpd.conf
Listen 80
Listen 7000
Listen 8000
Listen 9000

SELinux guards our ports

If we try to restart our server, we will notice the following error:

[root@CentOS65 ~]# service httpd restart
Stopping httpd:                                            [  OK  ]
Starting httpd: 
       (13)Permission denied: make_sock: could not bind to address 0.0.0.0:7000
no listening sockets available, shutting down
                                                           [FAILED]

This is due to SELinux reserving ports 7000 and 8000 for other uses. We need to tell SELinux we want to use these ports for http traffic

[root@CentOS65 ~]# semanage port -m -t http_port_t -p tcp 7000
[root@CentOS65 ~]# semanage port -m -t http_port_t -p tcp 8000
[root@CentOS65 ~]# service httpd restart
Stopping httpd:                                            [  OK  ]
Starting httpd:                                            [  OK  ]

three extra websites

Next we need to create three DocumentRoot directories.

[root@CentOS65 ~]# mkdir /var/www/html/choochoo
[root@CentOS65 ~]# mkdir /var/www/html/chessclub42
[root@CentOS65 ~]# mkdir /var/www/html/hunter2

And we have to put some really simple website in those directories.

[root@CentOS65 ~]# echo 'Choo Choo model train Choo Choo' > /var/www/html/chooc\
hoo/index.html
[root@CentOS65 ~]# echo 'Welcome to chess club 42' > /var/www/html/chessclub42/\
index.html
[root@CentOS65 ~]# echo 'HaCkInG iS fUn At HuNtEr2' > /var/www/html/hunter2/ind\
ex.html

enabling extra websites

The only way to enable or disable configurations in RHEL/CentOS is by renaming or moving the configuration files. Any file in /etc/httpd/conf.d ending on .conf will be loaded by Apache. To disable a site we can either rename the file or move it to another directory.

The files are created, so we can tell apache.

[root@CentOS65 ~]# ls /etc/httpd/conf.d/
chessclub42.conf  choochoo.conf  hunter2.conf  README  welcome.conf
[root@CentOS65 ~]# service httpd reload
Reloading httpd:

testing the three websites

Testing the model train club named Choo Choo on port 7000.

[root@CentOS65 ~]# wget 127.0.0.1:7000
--2014-05-11 11:59:36--  http://127.0.0.1:7000/
Connecting to 127.0.0.1:7000... connected.
HTTP request sent, awaiting response... 200 OK
Length: 32 [text/html]
Saving to: `index.html'

100%[===========================================>] 32          --.-K/s   in 0s

2014-05-11 11:59:36 (4.47 MB/s) - `index.html' saved [32/32]

[root@CentOS65 ~]# cat index.html 
Choo Choo model train Choo Choo

Testing the chess club named Chess Club 42 on port 8000.

[root@CentOS65 ~]# wget 127.0.0.1:8000
--2014-05-11 12:01:30--  http://127.0.0.1:8000/
Connecting to 127.0.0.1:8000... connected.
HTTP request sent, awaiting response... 200 OK
Length: 25 [text/html]
Saving to: `index.html.1'

100%[===========================================>] 25          --.-K/s   in 0s

2014-05-11 12:01:30 (4.25 MB/s) - `index.html.1' saved [25/25]

root@linux:/etc/apache2# cat index.html.1 
Welcome to chess club 42

Testing the hacker club named hunter2 on port 9000.

[root@CentOS65 ~]# wget 127.0.0.1:9000 
--2014-05-11 12:02:37--  http://127.0.0.1:9000/
Connecting to 127.0.0.1:9000... connected.
HTTP request sent, awaiting response... 200 OK
Length: 26 [text/html]
Saving to: `index.html.2'

100%[===========================================>] 26          --.-K/s   in 0s

2014-05-11 12:02:37 (4.49 MB/s) - `index.html.2' saved [26/26]

root@linux:/etc/apache2# cat index.html.2 
HaCkInG iS fUn At HuNtEr2

Cleaning up the temporary files.

[root@CentOS65 ~]# rm index.html index.html.1 index.html.2

firewall rules

If we attempt to access the site from another machine however, we will not be able to view the website yet. The firewall is blocking incoming connections. We need to open these incoming ports first

[root@CentOS65 ~]# iptables -I INPUT -p tcp --dport 80 -j ACCEPT
[root@CentOS65 ~]# iptables -I INPUT -p tcp --dport 7000 -j ACCEPT
[root@CentOS65 ~]# iptables -I INPUT -p tcp --dport 8000 -j ACCEPT
[root@CentOS65 ~]# iptables -I INPUT -p tcp --dport 9000 -j ACCEPT

And if we want these rules to remain active after a reboot, we need to save them

[root@CentOS65 ~]# service iptables save
iptables: Saving firewall rules to /etc/sysconfig/iptables:[  OK  ]

named virtual hosts on CentOS

named virtual hosts

The chess club and the model train club find the port numbers too hard to remember. They would prefere to have their website accessible by name.

We continue work on the same server that has three websites on three ports. We need to make sure those websites are accesible using the names choochoo.local, chessclub42.local and hunter2.local.

First, we need to enable named virtual hosts in the configuration

[root@CentOS65 ~]# vi /etc/httpd/conf/httpd.conf
[root@CentOS65 ~]# grep ^NameVirtualHost /etc/httpd/conf/httpd.conf
NameVirtualHost *:80
[root@CentOS65 ~]#

Next we need to create three new virtualhosts.

[root@CentOS65 ~]# vi /etc/httpd/conf.d/choochoo.local.conf
[root@CentOS65 ~]# vi /etc/httpd/conf.d/chessclub42.local.conf
[root@CentOS65 ~]# vi /etc/httpd/conf.d/hunter2.local.conf
[root@CentOS65 ~]# cat /etc/httpd/conf.d/choochoo.local.conf
<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        ServerName choochoo.local
        DocumentRoot /var/www/html/choochoo
</VirtualHost>
[root@CentOS65 ~]# cat /etc/httpd/conf.d/chessclub42.local.conf
<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        ServerName chessclub42.local
        DocumentRoot /var/www/html/chessclub42
</VirtualHost>
[root@CentOS65 ~]# cat /etc/httpd/conf.d/hunter2.local.conf
<VirtualHost *:80>
        ServerAdmin webmaster@localhost
        ServerName hunter2.local
        DocumentRoot /var/www/html/hunter2
</VirtualHost>
[root@CentOS65 ~]#

Notice that they all listen on port 80 and have an extra ServerName directive.

name resolution

We need some way to resolve names. This can be done with DNS, which is discussed in another chapter. For this demo it is also possible to quickly add the three names to the /etc/hosts file.

[root@CentOS65 ~]# grep ^192 /etc/hosts
192.168.1.225 choochoo.local
192.168.1.225 chessclub42.local
192.168.1.225 hunter2.local

Note that you may have another ip address...

reload and verify

After a service httpd reload the websites should be available by name.

[root@CentOS65 ~]# service httpd reload
Reloading httpd: 
[root@CentOS65 ~]# wget chessclub42.local
--2014-05-25 16:59:14--  http://chessclub42.local/
Resolving chessclub42.local... 192.168.1.225
Connecting to chessclub42.local|192.168.1.225|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 25 [text/html]
Saving to: âindex.htmlâ

100%[=============================================>] 25          --.-K/s   in 0s

2014-05-25 16:59:15 (1014 KB/s) - `index.html' saved [25/25]

[root@CentOS65 ~]# cat index.html
Welcome to chess club 42

password protected website on CentOS

You can secure files and directories in your website with a .htaccess file that refers to a .htpasswd file. The htpasswd command can create a .htpasswd file that contains a userid and an (encrypted) password.

This screenshot creates a user and password for the hacker named cliff and uses the -c flag to create the .htpasswd file.

[root@CentOS65 ~]# htpasswd -c /var/www/.htpasswd cliff
New password: 
Re-type new password: 
Adding password for user cliff
[root@CentOS65 ~]# cat /var/www/.htpasswd
cliff:QNwTrymMLBctU

Hacker rob also wants access, this screenshot shows how to add a second user and password to .htpasswd.

[root@CentOS65 ~]# htpasswd /var/www/.htpasswd rob
New password: 
Re-type new password: 
Adding password for user rob
[root@CentOS65 ~]# cat /var/www/.htpasswd
cliff:QNwTrymMLBctU
rob:EC2vOCcrMXDoM
[root@CentOS65 ~]#

Both Cliff and Rob chose the same password (hunter2), but that is not visible in the .htpasswd file because of the different salts.

Next we need to create a .htaccess file in the DocumentRoot of the website we want to protect. This screenshot shows an example.

[root@CentOS65 ~]# cat /var/www/html/hunter2/.htaccess 
AuthUserFile /var/www/.htpasswd
AuthName "Members only!"
AuthType Basic
require valid-user

Note that we are protecting the website on port 9000 that we created earlier.

And because we put the website for the Hackerspace named hunter2 in a subdirectory of the default website, we will need to adjust the AllowOvveride parameter in /etc/httpd/conf/httpd.conf under the <Directory "/var/www/html"> directive as this screenshot shows.

[root@CentOS65 ~]# vi /etc/httpd/conf/httpd.conf

<Directory "/var/www/html">

# 
# Possible values for the Options directive are "None", "All",
# or any combination of:
#   Indexes Includes FollowSymLinks SymLinksifOwnerMatch ExecCGI MultiViews
# 
# Note that "MultiViews" must be named *explicitly* --- "Options All"
# doesn't give it to you.
# 
# The Options directive is both complicated and important.  Please see
# http://httpd.apache.org/docs/2.2/mod/core.html#options
# for more information.
# 
    Options Indexes FollowSymLinks

# 
# AllowOverride controls what directives may be placed in .htaccess files.
# It can be "All", "None", or any combination of the keywords:
#   Options FileInfo AuthConfig Limit
#  
    AllowOverride Authconfig

# 
# Controls who can get stuff from this server.
# 
    Order allow,deny
    Allow from all

</Directory>

Now restart the apache2 server and test that it works!

troubleshooting apache

When apache restarts, it will verify the syntax of files in the configuration folder /etc/apache2 on debian or /etc/httpd on CentOS and it will tell you the name of the faulty file, the line number and an explanation of the error.

root@linux:~# service apache2 restart
apache2: Syntax error on line 268 of /etc/apache2/apache2.conf: Syntax error o\
n line 1 of /etc/apache2/sites-enabled/chessclub42: /etc/apache2/sites-enabled\
/chessclub42:4: <VirtualHost> was not closed.\n/etc/apache2/sites-enabled/ches\
sclub42:1: <VirtualHost> was not closed.
Action 'configtest' failed.
The Apache error log may have more information.
 failed!

Below you see the problem... a missing / before on line 4.

root@linux:~# cat /etc/apache2/sites-available/chessclub42
<VirtualHost *:8000>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/chessclub42
<VirtualHost>

Let us force another error by renaming the directory of one of our websites:

root@linux:~# mv /var/www/choochoo/ /var/www/chooshoo
root@linux:~# !ser
service apache2 restart
Restarting web server: apache2Warning: DocumentRoot [/var/www/choochoo] does n\
ot exist
Warning: DocumentRoot [/var/www/choochoo] does not exist
 ... waiting Warning: DocumentRoot [/var/www/choochoo] does not exist
Warning: DocumentRoot [/var/www/choochoo] does not exist
.

As you can see, apache will tell you exactly what is wrong.

You can also troubleshoot by connecting to the website via a browser and then checking the apache log files in /var/log/apache.

virtual hosts example

Below is a sample virtual host configuration. This virtual hosts overrules the default Apache ErrorDocument directive.

<VirtualHost 83.217.76.245:80>
ServerName cobbaut.be
ServerAlias www.cobbaut.be
DocumentRoot /home/paul/public_html
ErrorLog /home/paul/logs/error_log
CustomLog /home/paul/logs/access_log common
ScriptAlias /cgi-bin/ /home/paul/cgi-bin/
<Directory /home/paul/public_html>
    Options Indexes IncludesNOEXEC FollowSymLinks
    allow from all
</Directory>
ErrorDocument 404 http://www.cobbaut.be/cobbaut.php
</VirtualHost>

aliases and redirects

Apache supports aliases for directories, like this example shows.

Alias /paul/ "/home/paul/public_html/"

Similarly, content can be redirected to another website or web server.

Redirect permanent /foo http://www.foo.com/bar

more on .htaccess

You can do much more with .htaccess. One example is to use .htaccess to prevent people from certain domains to access your website. Like in this case, where a number of referer spammers are blocked from the website.

student@linux:~/cobbaut.be$ cat .htaccess 
# Options +FollowSymlinks
RewriteEngine On
RewriteCond %{HTTP_REFERER} ^http://(www\.)?buy-adipex.fw.nu.*$ [OR]
RewriteCond %{HTTP_REFERER} ^http://(www\.)?buy-levitra.asso.ws.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} ^http://(www\.)?buy-tramadol.fw.nu.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} ^http://(www\.)?buy-viagra.lookin.at.*$ [NC,OR]
...
RewriteCond %{HTTP_REFERER} ^http://(www\.)?www.healthinsurancehelp.net.*$ [NC]
RewriteRule .* - [F,L]
student@linux:~/cobbaut.be$

traffic

Apache keeps a log of all visitors. The webalizer is often used to parse this log into nice html statistics.

self signed cert on Debian

Below is a very quick guide on setting up Apache2 on Debian 7 with a self-signed certificate.

Chances are these packages are already installed.

root@linux:~# aptitude install apache2 openssl
No packages will be installed, upgraded, or removed.
0 packages upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B of archives. After unpacking 0 B will be used.

Create a directory to store the certs, and use openssl to create a self signed cert that is valid for 999 days.

root@linux:~# mkdir /etc/ssl/localcerts
root@linux:~# openssl req -new -x509 -days 999 -nodes -out /etc/ssl/local\
certs/apache.pem -keyout /etc/ssl/localcerts/apache.key
Generating a 2048 bit RSA private key
...
...
writing new private key to '/etc/ssl/localcerts/apache.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:BE
State or Province Name (full name) [Some-State]:Antwerp
Locality Name (eg, city) []:Antwerp
Organization Name (eg, company) [Internet Widgits Pty Ltd]:linux-training.be
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:Paul
Email Address []:

A little security never hurt anyone.

root@linux:~# ls -l /etc/ssl/localcerts/
total 8
-rw-r--r-- 1 root root 1704 Sep 16 18:24 apache.key
-rw-r--r-- 1 root root 1302 Sep 16 18:24 apache.pem
root@linux:~# chmod 600 /etc/ssl/localcerts/*
root@linux:~# ls -l /etc/ssl/localcerts/
total 8
-rw------- 1 root root 1704 Sep 16 18:24 apache.key
-rw------- 1 root root 1302 Sep 16 18:24 apache.pem

Enable the apache ssl mod.

root@linux:~# a2enmod ssl
Enabling module ssl.
See /usr/share/doc/apache2.2-common/README.Debian.gz on how to configure SSL\
 and create self-signed certificates.
To activate the new configuration, you need to run:
  service apache2 restart

Create the website configuration.

root@linux:~# vi /etc/apache2/sites-available/choochoos
root@linux:~# cat /etc/apache2/sites-available/choochoos
<VirtualHost *:7000>
        ServerAdmin webmaster@localhost
        DocumentRoot /var/www/choochoos
        SSLEngine On
        SSLCertificateFile /etc/ssl/localcerts/apache.pem
        SSLCertificateKeyFile /etc/ssl/localcerts/apache.key
</VirtualHost>
root@linux:~#

And create the website itself.

root@linux:/var/www/choochoos# vi index.html
root@linux:/var/www/choochoos# cat index.html
Choo Choo HTTPS secured model train Choo Choo

Enable the website and restart (or reload) apache2.

root@linux:/var/www/choochoos# a2ensite choochoos
Enabling site choochoos.
To activate the new configuration, you need to run:
  service apache2 reload
root@linux:/var/www/choochoos# service apache2 restart
Restarting web server: apache2 ... waiting .

Chances are your browser will warn you about the self signed certificate.

self signed cert on RHEL/CentOS

Below is a quick way to create a self signed cert for https on RHEL/CentOS. You may need these packages:

[root@paulserver ~]# yum install httpd openssl mod_ssl
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: ftp.belnet.be
 * extras: ftp.belnet.be
 * updates: mirrors.vooservers.com
base                                                         | 3.7 kB     00:00
Setting up Install Process
Package httpd-2.2.15-31.el6.centos.x86_64 already installed and latest version
Package openssl-1.0.1e-16.el6_5.15.x86_64 already installed and latest version
Package 1:mod_ssl-2.2.15-31.el6.centos.x86_64 already ins... and latest version
Nothing to do

We use openssl to create the certificate.

[root@paulserver ~]# mkdir certs
[root@paulserver ~]# cd certs
[root@paulserver certs]# openssl genrsa -out ca.key 2048
Generating RSA private key, 2048 bit long modulus
.........+++
.........................................................+++
e is 65537 (0x10001)
[root@paulserver certs]# openssl req -new -key ca.key -out ca.csr
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [XX]:BE
State or Province Name (full name) []:antwerp
Locality Name (eg, city) [Default City]:antwerp
Organization Name (eg, company) [Default Company Ltd]:antwerp
Organizational Unit Name (eg, section) []:
Common Name (eg, your name or your server's hostname) []:paulserver
Email Address []:

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
An optional company name []:
[root@paulserver certs]# openssl x509 -req -days 365 -in ca.csr -signkey ca.ke\
y -out ca.crt
Signature ok
subject=/C=BE/ST=antwerp/L=antwerp/O=antwerp/CN=paulserver
Getting Private key

We copy the keys to the right location (You may be missing SELinux info here).

[root@paulserver certs]# cp ca.crt /etc/pki/tls/certs/
[root@paulserver certs]# cp ca.key ca.csr /etc/pki/tls/private/

We add the location of our keys to this file, and also add the NameVirtualHost *:443 directive.

[root@paulserver certs]# vi /etc/httpd/conf.d/ssl.conf
[root@paulserver certs]# grep ^SSLCerti /etc/httpd/conf.d/ssl.conf
SSLCertificateFile /etc/pki/tls/certs/ca.crt
SSLCertificateKeyFile /etc/pki/tls/private/ca.key

Create a website configuration.

[root@paulserver certs]# vi /etc/httpd/conf.d/choochoos.conf
[root@paulserver certs]# cat /etc/httpd/conf.d/choochoos.conf
<VirtualHost *:443>
        SSLEngine on
        SSLCertificateFile /etc/pki/tls/certs/ca.crt
        SSLCertificateKeyFile /etc/pki/tls/private/ca.key
        DocumentRoot /var/www/choochoos
        ServerName paulserver
</VirtualHost>
[root@paulserver certs]#

Create a simple website and restart apache.

[root@paulserver certs]# mkdir /var/www/choochoos
[root@paulserver certs]# echo HTTPS model train choochoos > /var/www/choochoos/\
index.html
[root@paulserver httpd]# service httpd restart
Stopping httpd:                                            [  OK  ]
Starting httpd:                                            [  OK  ]

And your browser will probably warn you that this certificate is self signed.

practice: apache

1. Verify that Apache is installed and running.

2. Browse to the Apache HTML manual.

3. Create three virtual hosts that listen on ports 8472, 31337 and 1201. Test that it all works.

4. Create three named virtual hosts startrek.local, starwars.local and stargate.local. Test that it all works.

5. Create a virtual hosts that listens on another ip-address.

6. Protect one of your websites with a user/password combo.