Setup Secondary Mail Relay

[kilburn]

Yeah, it is correct, but I wouldn't recommend you to set MX records for unexistant mail servers. We (company.tld) solved this issue by adding a dns record mailers.company.tld that resolves to all our managed IP's:

Code:

...
mailers.company.tld.     IN    A     IP.OF.SRV.1
mailers.company.tld.     IN    A     IP.OF.SRV.2
mailers.company.tld.     IN    A     IP.OF.SRV.3
...

Then we modified the templates so the spf record is statically set to:

Code:

v=spf1 a:mailers.company.tld -all

This way, all -and only- our servers are automatically authorized to send mails for all our managed domains. The great thing about this is that we just need to add/remove the corresponding A entry when we add a new server or remove an old one, without worrying about the actual domain's configuration.