This is an article I wrote once for my blog. I figured it might be useful for a lot of hosts, so here it is.
As owner of a hosting provider company, I face the problem of abusive users almost every day. More than 90% of all abuse on my server comes from free trial accounts. I offer free trial access to my servers for people who want to try things out before they purchase a hosting package, but off course this attracts spammers. To prevent trial users from using my server for spamming purposes, I modified my exim.pl file to prevent trial users from accessing the Exim mail server.
Please note that this tutorial has been written for cPanel servers.
First you’ll need to download, compile and install my
cpgetpack.c application. Here’s how:
Code:
gcc cpgetpack.c -o cpgetpack
mv cpgetpack /usr/bin/
chown cpanel:cpanel /usr/bin/cpgetpack
chmod +s /usr/bin/cpgetpack
Now open the /etc/exim.pl file in your favorite text editor (make a backup first) and look for the following inside the checkuserpass subroutine:
Code:
$trueowner =~ s////g;
$trueowner =~ s/..//g;
if (isdemo(${trueowner})) {
return('no');
}
Below, paste the following code:
Code:
my $name = getpwuid($uid);
open(UP, "cpgetpack $name|");
my $userplan = ;
close(UP);chop($userplan);
if ($userplan eq "radix_FreeTrial") {
return "no";
}
You will have to replace the radix_FreeTrial string with the package you assign to your trial users. This will prevent trial users from authenticating which prevents them from sending mail remotely. However, they are still able to send mail locally (for example using the PHP mail() function), so here’s what to do next: find the checkdemo subroutine in the exim.pl file and replace the complete subroutine with:
Code:
sub democheck {
my $uid = Exim::expand_string('$originator_uid');
if (isdemo($uid)) { return 'yes'; }
my $name = getpwuid($uid);
open(UP, "cpgetpack $name|");
my $userplan = ;
close(UP);
chop($userplan);
if ($userplan eq "radix_FreeTrial") {
return 'yes';
}
return 'no';
}
Now just restart Exim:
Code:
service exim restart
It might be a good idea to create a trial account and see if it’s working. Enjoy!
