Once you have installed Neomail application on your server, edit the httpd.conf file:
# vi /usr/local/apache/conf/httpd.conf
Find the “ScriptAlias” string.
ScriptAlias /cgi-bin/ “/usr/local/apache/cgi-bin/”
Just add the following line under the above line.
ScriptAlias /mail “/usr/local/apache/cgi-bin/plugins/neomail/neomail.pl”
Now save the file & restart apache service
# service httpd start