Hotmail users cannot receive attachments from usermin senders

We’re using the usermin webmail component of the virtualmin commercial product. We recently transitioned some customers from an older GPL webmin/usermin to this latest version of virtualmin running on CentOS 4.8. Apparently there is a difference in the way that multipart mail messages are assembled in usermin as messages sent with attachments can no longer be viewed by anyone with a Hotmail on the receiving end. The default setup works, however, when you change the mail preferences to “Use HTML editor for composing” to “Always” instead of the default never, the problem occurs. I’ve never run into this before I guess, because it worked on the older version (webmin 1.420/usermin 1.350), and, our customers do not typically send HTML mail. Interestingly enough, mail sent in this fashion to gmail works. Also, normal mail clients like Thunderbird work perfectly. I’m sure this is probably a case of Hotmail not following some rule, however, I’m pretty sure they will be less than supportive when try to blame it on them. Any suggestions on how to fix this? Should I file a bug report?

Do you happen to have an example message for each case – one that works, and one that doesn’t?

If we can figure out where exactly things aren’t working, we can see if it requires a config change, or a bugfix… thanks!



I see what you are saying, unfortunately I’m not really sure how to get these out of Webmail, especially at the Hotmail end. Even if you try to view the page source, there is nothing really there. Everything seems to be hidden. This is easily demonstrable though. Anyone can duplicate this simply by sending an HTML mail in Webmin and attaching any image. When you login to your Hotmail account, you will see no trace of the image. I have always debugged mail issues where I could see the message source clearly in a traditional mail client. I really have gained a new appreciation for those who write Webmail applications after seeing something like this, not to mention, I’m sure the rules are always changing.


was this filed as a bug report?

I’ve found that this is happening with forwarded emails through to yahoo - the attachment disappears. It works when sending to gmail. What is also strange is that in hotmail, the attachment icon appears, and when I view source can see the attachments, however when I click through to view the full message, no attachment appears.

Yeah I’d recommend filing it as a bug report – I think we’re going to need Jamie’s thoughts on all that :slight_smile: