LTMPD rejecting large messages, maxmessagesize is _not_ set

[Chris St. Pierre]

On Fri, 13 Jul 2007, Chris St. Pierre wrote:

> On Fri, 13 Jul 2007, David Carter wrote:
>
>> On Tue, 10 Jul 2007, Chris St. Pierre wrote:
>>
>>>  LMTPD is rejecting large messages; I've been unable to figure out the exact
>>>  threshold, but I am seeing messages like this in my Postfix logs:
>>>
>>>  Jun 28 20:23:12 vostok postfix/qmgr[9323]: 22F5373D6F6:
>>>  from=<sender at example.com>, size=16243464, nrcpt=1 (queue active) Jun 28
>>>  20:23:22 vostok postfix/lmtp[13405]: warning: non-LMTP response from
>>>  imap.nebrwesleyan.edu[10.1.1.31]: sendmail: fatal: sender at example.com(76):
>>>  Message file too big
>>
>> I don't think that Cyrus generated that error messages. Try "strings" on the
>> lmtpd binary. Errors from Cyrus should be all variants on:
>>
>>   ec IMAP_MESSAGE_TOO_LARGE,
>>    "Message size exceeds fixed limit"
>>
>> Is sendmail/postfix using a staging partition which has run out space?
>
> Right you are.  It's Postfix's 'sendmail' binary that appears to be
> generating the error, although I'm still perplexed that it claims to
> be in response to a non-LMTP response from lmtpd.

Some investigation confirmed my initial suspicions: that Cyrus lmtpd
is returning to Postfix's lmtp delivery daemon the message:

"sendmail: fatal: sender at example.com(76): Message file too big"

Since that doesn't start with [2-5]\d\d, it's not a valid LMTP
response, and Postfix is doing the right thing by complaining.

Why would Cyrus return that?  Obviously something is wrong with the
delivery, but under what circumstances would a) lmtpd invoke the
sendmail binary? b) sendmail fail thusly? c) lmtpd pass the failure
message, unadorned, back to the sender?  The latter in particular
seems like broken behavior; shouldn't lmtpd return something like '5xx
sendmail: fatal: ...'?

There's plenty of free space everywhere, and message size limits are
either set high or not at all.

Any ideas?  Thanks!

Chris St. Pierre
Unix Systems Administrator
Nebraska Wesleyan University
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