WG: Message contains NUL characters - howto dump?

Klemens Puritscher cyrus at puri.jet2web.at
Thu Apr 16 11:07:16 EDT 2009

Please, can somebody help me?
Maybe, it's a problem in the cyrus lmtp-daemon? (I don't think so...)



----- Weitergeleitete Nachricht -----
Datum: Wed, 15 Apr 2009 16:18:46 +0200 (CEST)
Von: Klemens Puritscher <cyrus at puri.jet2web.at>
An: info-cyrus at lists.andrew.cmu.edu
Betreff: *****POSSIBLE SPAM***** Message contains NUL characters - howto dump?


I have a problem with one of our customers.
When he forwards an email with the thunderbird email client (windows version), the lmtp-daemon on my cyrus-imapd (v2.3.13) rejects those emails with the error "554 5.6.0 Message contains NUL characters".
...ok, that's clear, there are "NUL" characters in the email.

But I would show my customer, where the "NUL" character is.

For tests, I generate a testmail, with "echo -e "From:<sender at example.com>\nTo:<recipient at example.com>\nSubject: test\n\ntest\0000test\n.\n" > mail_with_NUL.txt

Now I dump the lmtp-session on the cyrus-imapd host with:
tcpdump -vv -XX -s 65535 -n -i eth1 "port lmtp

and I see the "NUL" character:
        0x0230:  7065 6564 2e61 740d 0a0d 0a74 6573 7400  peed.at....test.
        0x0240:  7465 7374 0d0a 2e0d 0a                   test.....
65 = e
73 = s
74 = t
00 = NUL

...ok, fine, I can find the "NUL" character.

But when I dump the lmtp-session with the customer email (which get's the error "554 5.6.0 Message contains NUL characters"), I cannot find this "NUL" character.

Can someone tell me, what I did wrong?

Thanks in advance.


Cyrus Home Page: http://cyrusimap.web.cmu.edu/
Cyrus Wiki/FAQ: http://cyrusimap.web.cmu.edu/twiki
List Archives/Info: http://asg.web.cmu.edu/cyrus/mailing-list.html

More information about the Info-cyrus mailing list