Frontline softworks

Courier-IMAP-SSL/TLS: Thunderbird error

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The problem: Using an IMAP TLS mail account on Thunderbird could give an error:

Thunderbird can’t connect securely to because the site uses a security protocol which isn’t enabled.

Why: Looking at the the maillog (tail -f /usr/local/psa/var/log/maillog) we got:

imapd: couriertls: accept: error:1408A10B:SSL routines:SSL3_GET_CLIENT_HELLO:wrong version number

Solution: Edit /etc/courier-imap/imapd-ssl and check the values to match this:

# TLS_PROTOCOL sets the protocol version.
TLS_PROTOCOL=SSL23

# TLS_STARTTLS_PROTOCOL is used instead of TLS_PROTOCOL for the IMAP STARTTLS extension, as opposed to IMAP over SSL on port 993.
TLS_STARTTLS_PROTOCOL=TLS1

It seems that these two TLS protocol directives do not want to be identical.

Reload the IMAP daemon and QMail daemon, and the problem shoud be gone:

/etc/init.d/qmail restart
/etc/init.d/courier-imap restart

Have fun

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Tags: courier, Courier-IMAP, IMAP, IMAP TLS, QMail, TLS

This entry is filed under Debian, Linux, Plesk.