Error 451: Nameserver timeout

[Fr. Peter Jenner]

Dear all,

I have recently come across the following error message in my
/var/log/maillog file. It only seems to affect mail redirection to the
mail servers of Demon Internet Limited (www.demon.net).

May 22 22:04:59 ns sendmail[23529]: KAA19275:
to=<???@???????.org>, delay=3+11: 45:44, xdelay=00:00:00,
mailer=esmtp, relay=punt-1.mail.demon.net.,
stat=Deferred: 451 Nameserver timeout during parsing

(BTW I have changed the email address to ???@???????.org to prevent my
client being spammed.)

It is a real problem as the mail is currently stuck on my server. I
have tried to find some documentation on this error message but have
failed so I would welcome any pointer anyone can give me.

Thank you in anticipation.
--
Peter Jenner

[Chapter33]

"Fr. Peter Jenner" <p...@catholic.org> writes:
> It only seems to affect mail redirection to the
> mail servers of Demon Internet Limited (www.demon.net).
>
> May 22 22:04:59 ns sendmail[23529]: KAA19275:
> to=<???@???????.org>, delay=3+11: 45:44, xdelay=00:00:00,
> mailer=esmtp, relay=punt-1.mail.demon.net.,
> stat=Deferred: 451 Nameserver timeout during parsing

That's a DNS problem. This is what I would do next:

nslookup -query=mx ???????.org <~~ replace with correct domain name

If this fails, try:

nslookup -query=mx sendmail.org

If this also fails, check your DNS config files or talk to your ISP (or maybe
you have a different version of nslookup and I've given you the wrong syntax!).

If the latter works, it's likely to be a problem more specific to the mail
system you are sending to and as such, most likely out of your hands.

Mark Bannister.
mailto: m.ban...@research-int.com
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