Banner/Reverse DNS for Dedicated IPs

Shane3673

Well-Known Member
Dec 20, 2013
96
1
8
cPanel Access Level
Root Administrator
I have dedicated IPs setup for every domain we host that has email. I have Reverse DNS setup correctly so that the dedicated IPs resolve to mail.(domain).com. I get an error when doing mail server test because it says the email header does not match reverse DNS. The hostname of the server does not match these domain because it is part of only one of the domains, our main domain. Somehow I need to make it so each domain uses a different header so it matches the reverse DNS records. Changing the hostname will not help because it will only fix one domain and we plan on having at least 10 that use email on the server, all using different dedicated IPs. Also it is set up to send out mail using the dedicated IPs in case one gets blacklisted so the other domains will still work. Is this possible and how can I do it?

Thank you
 

Shane3673

Well-Known Member
Dec 20, 2013
96
1
8
cPanel Access Level
Root Administrator
I got it to work by doing this:

Adding this to Exim advanced editor:

smtp_active_hostname = ${lookup{$interface_address}lsearch{/etc/domainips}{host.$value}{$primary_hostname}}

Changing this in Exim advanced editor:

smtp_banner = "${smtp_active_hostname}

I just changed that part and left the rest the same. Now when I telnet to mail.domain.com on port 25, banner and helo say host.domain.com as long as it is on a dedicated IP, shared IP still shows hostname, which is fine because I don't have email on shared IP in case of blacklisting of domains. Gets rid of banner errors, you could change it a bit to make it say mail.domain.com but this way works for the errors. Found the code here:

Exim customization | 17391 - Page 2 | JaguarPC