aliased domain does not reject mail for non-existant user

[DCNet_James]

I've discovered an issue where I've added an aliased domain to one of the domains I'm hosting. My border mail servers do a call forward are properly rejected for non existent users on any hosted domain, but on an alias, this is not the case. I know the chkrcptto plugin does this check, and I think the file it checks is the PRODUCTROOT/qmail/control/rejectnonexist.

Why are alias domains not rejected like the main hosted domain is that its aliased to does?

Anyone have any insight on this, would be appreciated.

Thx
J

 

[DCNet_James]

I found this...
This may be elsewhere on the forums,and I know it was discussed when people were patching qmail in earlier plesk versions. But here is a synopsis of an issue we've been looking to resolve and a temporary workaround.

Plesk 8 does implement recipient checking via chkrcptto. However, domain aliases are not added to the rejectnonexist file.

As a result, dictionary attacks and spoof reply-to's sent to unknown users will generate a bounce.

Spamcop now treats backscatter as spam, and we've seen several people listed after either a dictionary attacks or large volumes of spam with spoofed header information.



Workaround
=========================================
You can add the aliased domain to the rejectnonexist file in /var/qmail/control but this will fail because the virtual domain does not exist in the mailnames directory.

Right now, we've created a symlink from the virtual domain name to the real domain name within the /var/qmail/mailnames folder.

This allows the chkrcptto to verify the user.

The chkrcptto plugin will have to be re-coded to allow checking of domain aliases.