Now we edit the /home/httpd/httpd_perl/conf/httpd.conf file. The first thing to do is to set a Port directive—it should be different from that used by the plain Apache server (Port 80), since we cannot bind two servers to the same port number on the same IP address. Here we will use 8000. Some developers use port 81, but you can bind to ports below 1024 only if the server has root permissions. Also, if you are running on a multiuser machine, there is a chance that someone already uses that port, or will start using it in the future, which could cause problems. If you are the only user on your machine, you can pick any unused port number, but be aware that many organizations use firewalls that may block some of the ports, so port number choice can be a controversial topic. Popular port numbers include 80, 81, 8000, and 8080. In a two-server scenario, you can hide the nonstandard port number from firewalls and users by using either mod_proxy's ProxyPass directive or a proxy server such as Squid.

Now we proceed to the mod_perl-specific directives. It's a good idea to add them all at the end of httpd.conf, since you are going to fiddle with them a lot in the early stages.

First, you need to specify where all the mod_perl scripts will be located. Add the following configuration directive:

# mod_perl scripts will be called from
Alias /perl /home/httpd/httpd_perl/perl

From now on, all requests for URIs starting with /perl will be executed under mod_perl and will be mapped to the files in the directory /home/httpd/httpd_perl/perl.

Now configure the /perl location:

PerlModule Apache::Registry

<Location /perl>
    #AllowOverride None
    SetHandler perl-script
    PerlHandler Apache::Registry
    Options ExecCGI
    PerlSendHeader On
    Allow from all

This configuration causes any script that is called with a path prefixed with /perl to be executed under the Apache::Registry module and as a CGI script (hence the ExecCGI—if you omit this option, the script will be printed to the user's browser as plain text or will possibly trigger a "Save As" window).

This is only a very basic configuration. Chapter 4 covers the rest of the details.

Once the configuration is complete, it's a time to start the server with:

/home/httpd/httpd_perl/bin/apachectl start