Discovery of the month
I have discovered a problem which can be recreated at will. Red Hat 7.3 running QMail mail server will generate errors with certain types of email clients when an attachment is present.
The errors include;
Microsoft Outlook 2000 SP1
Mail could not be sent Error 354 Server said Go Ahead
Microsoft Outlook 97 and Microsoft Outlook Express 6.0
Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity. Subject '', Account: 'mail.server.com', Server: 'mail.server.com', Protocol: SMTP, Port: 25, Secure(SSL): No, Error Number: 0x800CCC0F
Thunderbird 1.0
The message could not be sent because the connection to the SMTP server failed.
The server may be unavailable or may be refusing SMTP connections.
The Facts
· This occurs on Windows 2000 and Windows XP fully patched
· This can be recreated at will and has been tested on 5 different networks using 4 different upstream providers
· This does NOT occur when using Outlook 2000 which is patched up to date
· With Thunderbird, it only occurs when the sender and recipient are on the same server
· This has been tested with AUTO MTU on and off
At the time of this writing the actual cause is unknown and is under investigation.