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Re: Off-topic: mydnsbl (my "too many failures BL") moving from investigation to testing

2005-01-17 15:27:05
On Mon, Jan 17, 2005 at 03:01:48PM -0700, 
administrator(_at_)yellowhead(_dot_)com wrote:

I tried to send this to you directly, but your server rejected it with the
following message:
Diagnostic-Code: SMTP; 450 Client host rejected: cannot find your hostname,
[69.36.102.205]

69.36.102.205 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  69.36.102.205" will be enough.

HTH
Alex


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