Thunderbird Connection Timeout

Background

We often see problems in our mail server (mail.cs) when clients start creating multiple Imap sessions when the system is running slowly. This has the effect of exacerbating the problem and may bring the entire server down. By default, Thunderbird is configured to retry making a connection if it doesn't receive a complete response after 60 seconds. When mailboxes are large and the server is busy, it can easily require more than 60 seconds to complete a mail update. So, it spawns another session - leaving the old one behind. The number of processes builds up on the mail server until it eventually refuses to process mail at all. Not good.

Configuring Thunderbird for a 5-minute timeout

If we change the timeout from 60 seconds to 300 seconds, that seems to be manageable by the system. Usually, there is no noticeable impact on the user.

Steps for the configuration change (Thunderbird 2/3)

• Tools -> Options
• Click on the Advanced button
• Click on the "Network & Disk Space" tab
• Change "Connection timeout" to 300
• Click "Ok"