qmail at top-consulting
Feb 24, 2011, 4:12 PM
Post #3 of 3
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We do use a Barracuda Box in front. It's up to date and running properly.
Checking out the message in it clearly shows a new line between the
two References lines.
I guess the question now becomes if the Barracuda inserts that extra line.
If so, it's another bug in a loooong list...
Quoting Kevin Chadwick <ma1l1ists [at] yahoo>:
> On Thu, 24 Feb 2011 17:53:49 -0500
> qmail [at] top-consulting wrote:
>
>> I am having a world of trouble with messages that contain a References
>> header whenever that References line goes above 1000 characters.
>>
>> As per the RFC any one line can't have more than 1000 characters which
>> is totally fine. The problem however is that messages from a certain
>> person are coming up broken. Looking at the source of the messages I
>> see that the References line has been broken at the 1000 character
>> mark and an empty new line has been inserted. All e-mail clients
>> interpret that as being the end of the headers.
>>
>> I have recorded the SMTP conversation as I receive this particular
>> message and here's what happens at the 1000 character mark:
>>
>> @400000004d66d1113841ec94 11008 < 97B-8278-3415983066^M
>> @400000004d66d1113841f464 11008 < ^M
>> @400000004d66d1113841fc34 11008 < 13@
>>
>> Is that cutoff done by qmail itself or am I receiving that from the
>> remote end ?
>>
>> When the same person e-mails my Hotmail account for example, the
>> message arrives broken at the same spot but there's no new line
>> inserted like with Qmail.
>>
>> What's going on ?
>>
>>
>
> The following mails were fired across not long ago. Are you using a
> cisco or any proxy filter by any chance?
>
>
>
> _______________________________________________________________________
> From: Hugo Monteiro <hugo.monteiro [at] fct>
> To: qmail [at] list
> Subject: Re: Dropped connections with header lines longer than 998
> characters Date: Wed, 05 Jan 2011 19:54:55 +0000
> User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; PT-pt; rv:1.9.1.9pre)
> Gecko/20100217 Lightning/1.0b1 Shredder/3.0.3pre
>
> On 01/05/2011 06:52 PM, Charles Cazabon wrote:
>> Brent Gardner<brent.gardner [at] gmail> wrote:
>>
>>> I'm seeing an issue where qmail appears to be dropping connections from
>>> remote senders that try to send us messages with header lines that are
>>> longer than 998 characters.
>>>
>>> I'm running qmail as part of qmailtoaster, qmail is patched to
>>> netqmail-1.05.
>>>
>> Do you have any other patches or addons installed? My qmail does not do as
>> you say.
>>
>>
>>> This setup serves as a spam filter for our corporate Exchange server.
>>>
>> What are you using to scan messages for spam or viruses/trojans
>> during the SMTP
>> conversation? It looks like that program is probably at fault here.
>>
>> Charles
>>
>
> RFCs, from initial 821 through 5321 state:
>
> " The maximum total length of a text line including the <CRLF> is 1000
> octets"
>
> RFC5321 also states that
>
> " This number may be increased by the use of SMTP Service Extensions."
>
> So, if your qmail install doesn't support and advertise ESMTP line
> value, the client, or connecting server, has no business in trying to
> send lines longer than that. That limit was also set to avoid possible
> buffer overflows in less robust implementations.
>
> Regards,
>
> Hugo Monteiro.
>
>
> ______________________________________________________________________
> From: Brent Gardner <brent.gardner [at] gmail>
> To: qmail [at] list
> Subject: Re: Dropped connections with header lines longer than 998
> characters Date: Wed, 05 Jan 2011 18:01:21 -0700
> User-Agent: Thunderbird 2.0.0.21 (X11/20090320)
>
> Charles Cazabon wrote:
>> Brent Gardner <brent.gardner [at] gmail> wrote:
>>
>>> I'm seeing an issue where qmail appears to be dropping connections from
>>> remote senders that try to send us messages with header lines that are
>>> longer than 998 characters.
>>>
>>> I'm running qmail as part of qmailtoaster, qmail is patched to
>>> netqmail-1.05.
>>>
>>
>> Do you have any other patches or addons installed? My qmail does not do as
>> you say.
>>
>>
> The patch level is according to this page dated 2009-03-16 in the
> qmailtoaster wiki:
> http://wiki.qmailtoaster.com/index.php/Patches_included_with_QmailToaster.
> I haven't installed any other patches myself.
>
>>> This setup serves as a spam filter for our corporate Exchange server.
>>>
>>
>> What are you using to scan messages for spam or viruses/trojans
>> during the SMTP
>> conversation? It looks like that program is probably at fault here.
>>
>>
> I also run Spamdyke in front of qmail, but behavior is the same with or
> without Spamdyke enabled.
>
>
> I've determined the problem to be ESMTP filtering in our Cisco ASA.
> Annoyingly, that's the first thing I checked when this issue was
> brought to my attention. Guess I didn't check thoroughly enough.
>
> Charles, Hugo- thanks for your replies. They led me to new research
> paths which have increased my knowledge.
>
>
> Brent Gardner
>
> ________________________________________________________________________________
>
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