My notes, things I have learned, and documentation I have created.

When I did a new installation of Fedora 13 and configured Thunderbird 3.0.4 for IMAP, I found that the performance was just atrocious. It was downloading all the messages from all my folders.

The release notes for Thunderbird gave me a hint:

IMAP Folder Synchronization

Thunderbird will download IMAP messages by default in the background to allow for faster message loading and better offline operation. This feature can be enabled on an individual folder basis via Folder properties, or for all folders in an account via Account Settings / ‘Synchronize & Storage’.

——————–

I turned this “feature” off for my account. It is in “Account Settings” and then “Synchronization & Storage” for my IMAP account. From here, I unchecked “Keep messages for this account on this computer.” Also, I changed the “Disk Space” setting from “Synchronize all messages locally regardless of age” to “Synchronize the most recent 1 Weeks.” These two settings made a huge improvement to my performance. Yes, I lose offline access, but that does not matter to this desktop computer.

To send an email via telnet for testing:
telnet SMTP Server Name 25
EHLO mydomain.tld
MAIL FROM: my@from.address
RCPT TO: my@to.address
DATA
Here you can type the body of the message.
.

To the same thing, but with From: To: and Subject: headers:
telnet SMTP Server Name 25
EHLO mydomain.tld
MAIL FROM: my@from.address
RCPT TO: my@to.address
DATA
From: my@from.address
To: my@to.address
Subject: Here is a subject.

Here you can type the body of the message.
.

Here is how you can do a basic test of an IMAP server via telnet:

telnet IMAP Server Name 143
? LOGIN username password
? LIST “” “*”
? LOGOUT

This will log you in and list the accounts mail folders. Note: This is testing a basic unencrypted login to an IMAP server. Not the way you would want to implement in production, unless implement via localhost.

If you want to test your SSL configuration use openssl instead of telnet:
openssl s_client -connect hostname:portnumber

For example:
openssl s_client -connect SMTP Server Name:465