On Mon, Jan 17, 2005 at 03:01:48PM -0700,
I tried to send this to you directly, but your server rejected it with the
Diagnostic-Code: SMTP; 450 Client host rejected: cannot find your hostname,
22.214.171.124 resolves to mail.yellowhead.com.
mail.yellowhead.com. does not exist.
Therefore, mail.yellowhead.com. _cannot_ be THE canonical name
of the host. As such, your helo is invalid per RFC2821.
The host name definitely has an "A" record, and the IP definitely has a
reverse lookup. If you are checking that the hostname matches the reverse
lookup name, it will not always match. This is a very common situation when
a mail server is hosting several domains.
For any number of "several", all can point to a single IP address
that resolves to a hostname that resolves to the same IP address.
Adding "mail.yellowhead.com. A 126.96.36.199" will be enough.