AW: Re: Message contains NUL characters - howto dump?
cyrus at puri.jet2web.at
Fri Apr 17 03:29:14 EDT 2009
Phil Brutsche schrieb:
> The error message is being created by the LMTP service - NUL characters
> aren't valid in ASCII messages. The email in question is being generated
> incorrectly somewhere, somehow.
thanks for your reply.
I know that in the email must be a NUL character, but I cannot see this NUL character during a tcpdump.
Do you know, or someone else in this list, who can I safe find this NUL character?
> What you need to do is either have the MTA reject the message during the
> DATA portion of the SMTP transaction, or have the MTA remove the NUL
> characters before it passes the message on to the LMTP service.
Yes, this will be the next step.
> Your email headers indicate you are using Postfix as your MTA, and I am
> not familiar enough with that to tell you how to do what is necessary.
Yes, that's right for outgoing emails.
The MTA for incoming emails (mx host) is exim.
> Klemens Puritscher wrote:
> > Hello,
> > 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....
> > 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.
> > Klemens
> > ----
> > 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
> Phil Brutsche
> phil at optimumdata.com
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