I'm having an irregular issue with Zimbra and file attachments.
I'm running v3.1 on RHEL 4 (Twin 3Ghz Processors w/1Gb RAM)
Occassionally, when attachments are sent, they are being corrupted. I'm convinced it's being done by my Zimbra server as I've been able to replicate it with a specific message I have with attachments. I have been able to successfully receive this same message at my work email and at a gmail account without problems with the attachments.
The errors in my /var/log/zimbra.log file are:
Apr 21 10:49:45 email amavis: (25617-01) WARN: MIME::Parser error: part did not end with expected boundary
Apr 21 10:49:46 email amavis: (25617-01) spam_scan: not wasting time on SA, message longer than 65536 bytes: 1566+79606
Apr 21 10:49:46 email amavis: (25617-01) BAD HEADER from <email@example.com>: MIME error: error: part did not end with expected boundary
This behavior is seen regardless of whether I'm using the web frontend to Zimbra or using Thunderbird to connect via IMAP.