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.