If you are hosted with a WHM/Cpanel based server or VPS, you may have had some difficulties trying to get an alternate webserver such as Nginx or Lighttpd installed especially if you wanted to use the default port 80. This article shows you how you can release extra IP addresses to be used by those services without conflicting with Apache.
There are two areas wee need to address, Apache, and then WHM/Cpanel.
Apache
By default Apache listens to every interface coming into the machine by listening to 0.0.0.0:80/443. Normally you could edit the httpd.conf file directly in order to change the listen line, however that may cause problems with Cpanel’s automation.
To acheive this more safely, log into Webhost Manager (typically http://yourdomain.com/whm) and find Service Configuration followed by Apache Configuration. Then click on Reserved IPs Editor.
Here you will need to check the boxes of the IP addresses you do NOT wish for Apache to use. Once you save your selections, a new configuration file will be configured to listen on all the other IPs that were not checked. This will allow other services such as alternate webbrowsers to listen on those IP addresses without conflicting with Apache.
Webhost Manager
We freed some IP addresses from Apache, but now we have to make sure that WHM/Cpanel doesn’t attempt to use those same IP addresses for other services.
Navigate to IP Functions, followed by Show/Edit Reserved IPs. Here you should check the same IPs that were selected in the Apache Reserve list above. Once this is done WHM/Cpanel will avoid using those IP address when setting up new accounts and services.
Configuring Nginx
Assuming Nginx is already configured you will need to make a minor adjustment to the server blocks in order to start it up.
server {
listen an-ip-address:80;
server_name yourdomain.com www.yourdomain.com;
...
}Normally you would just have the port number identified, but if you tried to start it as just that, it would conflict with Apache if already running (otherwise vice-versa). So we need to make sure to bind each server block to an available IP address.
While I personally prefer to run Nginx standalone on it’s own server such as the one Kbeezie.com is running off of. Some may wish to use the benefits of Nginx for certain projects while still having the ease of use of Cpanel for other sites.
On a side note, if PHP is setup as a Fast-CGI executable in WHM you can share the same PHP instance with Nginx or Lighttpd, otherwise you’ll need to make sure to either compile a separate instance of PHP, or launch the fast-cgi daemon manually for the existing installation (spawn-fcgi, php-fpm, etc).