Redhat: Apache webserver Virtual Hosts

Virtual Hosts

Apache allows multiple websites to be hosted on the same system. This is useful given the limited number of IPv4 IP address available. This is done through virtual hosts that are defined in the httpd.comf file.

Regular Virtual Hosts

The first directive that must be enabled is:

NameVirutalHost *:80

To use name based hosts leave the asterisk after the directive. Otherwise set the IP address for the local interface.

Port 80 is the default port of web pages. To direct all requiests via IP 192.168.122.50 on port 80, the virtual host would be defined as shown. But in most cases you would use the above directive so that all websites. It also allows DHCP to work.

<VirtualHost 192.168.122.50:80>

Example Virtual Hosts

<VirtualHost *:80>
       ServerAdmin webmaster@boston1.example.com
       DocumentRoot /www/docs/boston1.example.com
       ServerName boston1.example.com
       ErrorLog logs/boston1.example.com-error_log
       EustomLof logs/boston1.example.com-error_log common
</VirtualHost>
<VirtualHost *:80>
       ServerAdmin webmaster@boston2.example.com
       DocumentRoot /www/docs/boston2.example.com
       ServerName boston2.example.com
       ErrorLog logs/boston2.example.com-error_log
       EustomLof logs/boston2.example.com-error_log common
</VirtualHost>

For the first Virtual Host:

• Error messages are emailed to webmaster@boston1.example.com
• Webpages are stored in teh DocumentRoot
• Clients call the websire through the server name
• The logs are sent to the paths relative to the Serverroot

Syntax Check

To check the syntax of the httpd.conf file run:

httpd -t
Syntax OK

Check Virtual Hosts

httpd -S
httpd -D DUMP_VHOSTS

Secure Virtual Hosts

For a webserver using https Redhat provides the ssl.conf file. In order to use this you will need to install mod_ssl using yum or RPM.

The ssl module needs to be loaded first:

LoadModule ssl_module modules/mod_ssl.so
Listen 443

There are a number of directives in ssl.conf, but no changes should be required.

Virtual Hosts are configures as before but with a slight difference. The port is 443 instead if 80.

In addition to the directives used define Standard Virtual Hosts, several SSL directives are added.

SSLEngine On
SSLProtocol all -SSLv2
SSLCipherSuite ALL: !ADH: !EXPORT: !SSLv2:RC4+RSA:+HIGH:+MEDIUM:+LOW
SSLCertificateFile /etc/pki/tls/certs/localhost.cert
SSLCertificateKeyFile /etc/pki/tls/private/localhost.key

To deal with IE browsers:

SetEnvIf User-Agent ".*MSIE.*" \
         nokeepalive ssl-unclean-shutdown \
         downgrade-1.0 force-response-1.0

SSL Certificates

The Default certificate listed in ssl.conf will work for basic configs, you may need to by a certificate from the Certificate Authority.

Within the /etc/pks/tls/certs directory is a makefile used to produce ssl certificates for each virtualhost. However used the certificate is produced by the CA, browers will still ask to use if the want to access the websites as it will be intrusted.

To generate a certificate and write the keys and certificates to the correct directories.

cd /etc/pks/tls/certs
genkey <hostname>