Hi. One of my company's customers requires mails to be sent to them to use TLS. Thanks to some good documentation on the web, I've got this mostly figured out, but now I'm stuck at generating the CSR.
My company's mail domain is sg.bunny.com (not real address, obviously), but the email gateway (running sendmail 8.14.4) has the following DNS records:
mail.sg.bunny.com 192.168.1.1 MX
eg1.bunny.com.sg 192.168.1.1 A
1.1.168.192.in-addr.arpa eg1.bunny.com.sg PTR
1.1.168.192.in-addr.arpa flop.bunny.com.sg PTR
Which hostname should I use for the CN on the cert? The one that corresponds to the MX record or the A record?
Don't ask me why the server is registered with 3 different names. No idea why my predecessor did that.