We are using qmail as a mail server.
If a user sends an email that cannnot be delivered he get's a message back from qmail with some details about this error.
Hi. This is the qmail-send program at our.server.tld I'm afraid I wasn't able to deliver your message to the following addresses. This is a permanent error; I've given up. Sorry it didn't work out. <email@example.com>: 18.104.22.168 failed after I sent the message. Remote host said: 552 5.3.4 Message is too large, rejected. --- Below this line is a copy of the message. ... header information ... ... message ... ... attachments in base64 ... ------_=_NextPart_001_000A0F27.508A4479-- ------_=_NextPart_000_000A0F27.508A4479 Content-Type: application/pdf; name="file.pdf" Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="file.pdf"; modification-date="Wed, 24 Oct 2012 14:27:24 +0000" JVBERi0xLjUNCiXi48/TDQo0IDAgb2JqDQo8PA0KL1R5cGUgL1BhZ2UNCi9QYXJlbnQgMiAwIFIN Ci9Db250ZW50cyA1IDAgUg0KL01lZGlhQm94IFstMC4wMDAwIC0wLjAwMDAgMTcwMC43ODc0IDIy ...
It is fine to have a copy of the message with the header and message information. But is it possible to tell qmail not to include the full attachment into this error message? This is a big overhead and it would be best to just limit the size of the message to a few kb since the user can't do anything with the base64 stream anyway.