Re: "Domain of sender address does not resolve" in mail logs
On Wed, Mar 18, 2009 at 11:26:14 +1100, Robert S (robert.spam.me.senseless@gmail.com) wrote:
> I have started getting a lot of these messages over the last few days
> in my mail logs. These messages refer to legitimate addresses eg:
>
> Mar 17 08:59:10 debian sm-mta[29154]: n2GLwjk7029154:
> ruleset=check_mail, arg1=<XXXXXXXXXX@act.gov.au>,
> relay=dmz017.dpa.act.gov.au [136.153.14.117], reject=451 4.1.8 Domain
> of sender address XXXXXXXX@act.gov.au does not resolve
> Mar 17 09:16:50 debian sm-mta[29224]: n2GMGPd8029224:
> ruleset=check_mail, arg1=<XXXXXXXX@gsahs.health.nsw.gov.au>,
> relay=mail.gsahs.health.nsw.gov.au [202.59.31.130], reject=451 4.1.8
> Domain of sender address XXXXXXXX@gsahs.health.nsw.gov.au does not
> resolve
> Mar 17 13:57:14 debian sm-mta[30575]: n2H2ullN030575:
> ruleset=check_mail, arg1=<news@tigerairwaysnews.com>,
> relay=mail.tigerairwaysnews.com [202.172.235.34], reject=451 4.1.8
> Domain of sender address news@tigerairwaysnews.com does not resolve
>
> It appears that at least some of the messages are actually getting
> through - there have been no complaints from the staff (maybe they
> just don't know whether the messages should have been sent!) and I
> sent a test email from one of these domains which got through -
> despite an error message in the log with my username from that domain.
>
> I use a Netgear DG834 router which is set to get DNS settings
> automatically from my ISP. I'm running Lenny (recently upgraded from
> Etch), Sendmail-8.14.3-5
>
> my /etc/resolv.conf
> domain XXXXXXX.net.au
> nameserver 192.168.0.1
>
> 192.168.0.1 is my router address
> NB: anything with XXXXXX is fictitious.
I am not an expert and use Postfix rather than Sendmail, but as far as I
can see this is an MTA configuration issue rather than a DNS problem.
Taking your first example:
Mar 17 08:59:10 debian sm-mta[29154]: n2GLwjk7029154:
ruleset=check_mail, arg1=<XXXXXXXXXX@act.gov.au>,
relay=dmz017.dpa.act.gov.au [136.153.14.117], reject=451 4.1.8 Domain
of sender address XXXXXXXX@act.gov.au does not resolve
As it says, the domain of sender address XXXXXXXX@act.gov.au does not
resolve - and it doesn't. There is no A record for act.gov.au (but
there is an MX record). Similarly, there is no A record for
gsahs.health.nsw.gov.au in your second example. This is more
interesting because the host is gsahs.health.nsw.gov.au, but AIUI the
domain is nsw.gov.au and that does have an A record.
The question is whether you should be rejecting email from any user
@act.gov.au just because act.gov.au does not resolve. As I understand
it, the important checking should be against the mail host - in the
first example this is dmz017.dpa.act.gov.au which correctly resolves to
136.153.14.117. Checking 136.153.14.117 shows that the reverse DNS is
also correctly set up.
(Your third example may have been a temporary problem as
tigerairwaysnews.com does have A and MX records in place).
--
Bob Cox. Stoke Gifford, near Bristol, UK.
Please reply to the list only. Do NOT send copies directly to me.
Debian on the NSLU2: http://bobcox.com/slug/
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