[Mailman-Users] Mailman cannot deliver email to a particular domain

Mark Sapiro mark at msapiro.net
Tue Nov 19 23:52:33 CET 2013

On 11/19/2013 02:24 PM, Hung Phan wrote:
> We have a particular issue with Mailman (more of an exim issue actually)


> ... it seems that Mailman thinks canby.k12... domain is hosted at 10.30.xxx.xx, which is our internal DNS service. Is there a tool for us to trace the email sending route? We suspect it is the DNS setting but need more info to determine where does it stop. Do we need an MX record, A record or something else in our DNS service so Mailman not try to connect to this DNS server and end up failing?

This has nothing to do with Mailman. It is strictly exim. Mailman is not
doing any DNS lookups on anything except maybe localhost or whatever is
set as SMTPHOST in Defaults.py/mm_cfg.py.

Mailman passes the message and list of recipient addresses to this SMTP
server (exim) and it's up to that server to deliver the mail.

You have MX records

$ dig mx canby.k12.or.us
canby.k12.or.us.	86400	IN	MX	60 ALT2.ASPMX.L.GOOGLE.com.
canby.k12.or.us.	86400	IN	MX	70 ASPMX2.GOOGLEMAIL.com.
canby.k12.or.us.	86400	IN	MX	70 ASPMX3.GOOGLEMAIL.com.
canby.k12.or.us.	86400	IN	MX	10 canby.k12.or.us.s9a1.psmtp.com.
canby.k12.or.us.	86400	IN	MX	20 canby.k12.or.us.s9a2.psmtp.com.
canby.k12.or.us.	86400	IN	MX	30 canby.k12.or.us.s9b1.psmtp.com.
canby.k12.or.us.	86400	IN	MX	40 canby.k12.or.us.s9b2.psmtp.com.
canby.k12.or.us.	86400	IN	MX	50 ASPMX.L.GOOGLE.com.
canby.k12.or.us.	86400	IN	MX	60 ALT1.ASPMX.L.GOOGLE.com.

If exim is trying to deliver mail to the canby.k12.or.us domain and
thinks it should be sent to, that's something to do with
exim and not Mailman.

Note: 10.x.x.x IP addresses are only valid within your local private
network. You don't have to mask them to protect your DNS since they
aren't accessible from outside your network.

You would probably have better luck taking this exim issue to an exim
support resource.

Mark Sapiro <mark at msapiro.net>        The highway is for gamblers,
San Francisco Bay Area, California    better use your sense - B. Dylan

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