Some clarity needed please

I finally have an IP address I can set for reverse DNS for my mail servers do I need to set it to the main domain or the

On MX toolbox I get the following errors:

  • Reverse DNS does not contain the hostname
  • Reverse DNS does not match SMTP Banner

How do I set the correct SMTP banner?

I have other domain names that I host (personal sites), would I get the same error for for these when using the other mail domain’s?

Thank you in advance, trying to learn more about how it works.

By default, the SMTP banner showed by Exim is the hostname of your server. You can view it easily connecting to your mail server:

$ telnet mail.yourdomain.tld 25
Connected to mail.yourdomain.tld.
Escape character is '^]'.
220  <-- this is the hostname you must use for the reverse dns

Edit: if you don’t have telnet installed and don’t want to install it, you can also use openssl:

$ openssl s_client -connect mail.yourdomain.tld:465 -quiet 2>/dev/null
220  <-- this is the hostname you must use for the reverse dns

If you use the hostname Exim is showing, you won’t have any problem.

1 Like

Thank you very much.

1 Like

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.