Accepting Incoming Mail from Specific Servers

[consultant]

We are using a third party SPAM filter service. However some spammers are ignoring our MX records and guessing at our end mail server address being the same IP as our webserver. We want to block all e-mail coming from mail servers other than our SPAM filter service.

One server it can be done at the TCP level since there is only one active domain.

Another server we want to block for just one of many domains being hosted on the server.

I've gotten a suggestion to create a tcpserver rules (tcp.smtp.cdb) file that by default denies connections but accepts from the IP address of our SPAM filter relay servers. This would be server-wide though so it wouldn't work on the server where we need to block for just one domain.

In addition, we have many clients using our server for outgoing SMTP via authentication so the solution can't cause their mail sending to stop working.

 

[stylefish]

Did you ever figure this out?

We've just started using a Spam filtering service (Tucows Email Defense by MX Logic). It works pretty well, but we have the same problem. Some domains use it some don't. So we can't issue a server-wide rule to allow incoming email from a specific IP.

 

[diemonde]

Did you ever find a solution for this?