[AusNOG] bigpond mail problems?

[Karl Auer]

On Mon, 2016-11-07 at 15:48 +1100, James Gray wrote:
> Unable to relay mail via Telstra's SMTP servers. Postfix is claiming
> "Host or domain name not found. Name service error for
> name=smtp.telstra.com type=MX: Host not found, try again" but doing a
> manual session to "smtp.telstra.com" from a TID service works fine
> (both unencrypted TCP/25 and encrypted TCP/465).

Why would you be looking up an MX record for smtp.telstra.com? Nobody
has addresses @smtp.telstra.com, do they?

I get servfail when I manually look up an MX for smtp.telstra.com:

kauer at kt:~$ dig  smtp.telstra.com mx
[...]
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 47180
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 1
[...]
;; QUESTION SECTION:
;smtp.telstra.com.		IN	MX
[...]

Leaving that aside: Our client's Exchange server is doing the same as
your Postfix server; reporting a DNS failure when the host system has
no problem resolving the name that allegedly can't be resolved.

And it is the servers themselves reporting the failure. They are not
reporting a rejection by a remote MTA, they are saying that they
themselves cannot resolve the relevant names.

Puzzzledly, K.

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Karl Auer (kauer at biplane.com.au)
http://www.biplane.com.au/kauer
http://twitter.com/kauer389

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