Some clarity needed please

Community Support
1

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 mail.domain.com?

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.

2

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
Trying 203.0.113.1...
Connected to mail.yourdomain.tld.
Escape character is '^]'.
220 here.you-will-see-the.hostname  <-- 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 here.you-will-see-the.hostname  <-- 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
3

Thank you very much.

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