[Mimedefang] Validating sender domain opinion
Steffen Kaiser
skmimedefang at smail.inf.fh-bonn-rhein-sieg.de
Thu Jul 8 09:37:16 EDT 2004
Hello,
there has been talk on the list placing 127.** or some other private
address as tarpit as MX record with least precedence.
What about a DNS configuration with an invalid private MX as first one?
I just test a sender validation by grabbing all MX's records and check if
the first one is an external address; doing so I found this domain:
; <<>> DiG 9.2.4rc5 <<>> -t mx mox.de.
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 29441
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 2, ADDITIONAL: 4
;; QUESTION SECTION:
;mox.de. IN MX
;; ANSWER SECTION:
mox.de. 252 IN MX 30 mail.portunity.de.
mox.de. 252 IN MX 10 192.168.100.251.
mox.de. 252 IN MX 20 mail.mox.de.
These are not spammers, BTW.
I would consider such setup invalid and my code had rejected the mail, if
it were enable. -- I mean, why does they try to deliver mail to one of my
hosts, private addresses are "my hosts", aren't they?
I ignore the fact here intentionally, that they do point to a numerical
address rather than a symbolic host.
What do you think?
Bye,
--
Steffen Kaiser
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