Mailing List CGatePro@mail.stalker.com Message #104527
From: Urs Grützner <ugruetzner@ems.ch>
Subject: Weird DNS Problem
Date: Thu, 17 Oct 2013 10:06:19 +0200
To: CommuniGate Pro Discussions <CGatePro@mail.stalker.com>
X-Mailer: Apple Mail (2.1084)
CGP 5.1.16 on Mac OS.X.5.8



We have a set up where mails to some of our users at @ems.ch are forwarded to another server emzurich.ems.ch

Problem: 
By coincidence I see in the queue, that a mail is not being forwarded since 2 days with the following log entry: 

09:35:49.970 1 SMTP-023132(emszurich.ems.ch) [5249863] return-path rejected, got:451 4.1.8 Sender address <Andrea.Stoll@nussli.com> domain does not resolve



When I make a look up the domain nussli.com however HAS a IN MX entry.
I have also verified that the DNS entries in the mail server System are correct, from our provider Swisscom 193.5.23.1, 193.247.204.1   


Questions:

- What does the log entry mean, which SMTP rejects? is it the sending SMTP (ems.ch) or is it the receiving SMTP (emszurich.ems.ch) which cannot resolve the domain nussli.com ?
- What happens when a forwarding finally  fails? Does the original sender get a Undelivery message? 


Thanks for help

Urs




; <<>> DiG 9.6-ESV-R4-P3 <<>> nussli.com any +multiline +nocomments +nocmd +noquestion +nostats +search
;; global options: +cmd
nussli.com. 3600 IN TXT "v=spf1 mx ptr a:smtp.nussli.com ip4:212.243.204.4/32 ip4:213.230.49.174/32 ?all"
nussli.com. 3600 IN MX 10 smtp.nussli.com.
2010051792 ; serial
10800      ; refresh (3 hours)
3600       ; retry (1 hour)
604800     ; expire (1 week)
3600       ; minimum (1 hour)
)
nussli.com. 3600 IN A 109.239.54.176
ns1.nussli.com. 124266 IN A 213.230.49.173
ns1.nussli.com. 124266 IN A 212.243.204.2
ns2.nussli.com. 94849 IN A 212.243.204.1
ns2.nussli.com. 94849 IN A 213.230.49.172

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