12 Nov
2007
12 Nov
'07
4:19 p.m.
Jonathan McDowell wrote:
You shouldn't use a CNAME for a host that you want to receive mail. I suggest you try changing it to an A record instead.
To quote RFC1123 section 5.2.2:
The domain names that a Sender-SMTP sends in MAIL and RCPT commands MUST have been "canonicalized," i.e., they must be fully-qualified principal names or domain literals, not nicknames or domain abbreviations. A canonicalized name either identifies a host directly or is an MX name; it cannot be a CNAME.
Can someone explain why this restriction exists (or point to a good resource)?
Regards,
--
Chris Lamb, UK chris@chris-lamb.co.uk
GPG: 0x634F9A20