About 95% of outgoing mail goes through, but I get sporadic undeliverable mail notifications while trying to connect to other mail servers.

<<< 500 couriertls: connect: error:1408F10B:SSL routines:SSL3_GET_RECORD:wrong version number

Courier 0.58.0
Courier Authlib 0.62.1
OpenSSL 0.9.8j

Where should I start to fix this issue?

2 Answers 2


Looks like there is a SSL version mismatch. Looks like your server is trying to handshake mail in v3 format, when the receiving server probably only accepts v2.

You should try enabling both v2 and v3 handshaking for your server.

  • Strange enough I thought I had done that, esmtpd config file has a line TLS_PROTOCOL=SSL23 which means SSL23 - either SSLv2 or SSLv3. Will look further in that direction, thanks
    – Wil
    May 29, 2009 at 13:55
  • I use this on my mailserver without a problem. TLS_PROTOCOL=SSL3 TLS_STARTTLS_PROTOCOL=TLS1 May 29, 2009 at 14:11

make sure the following line is correct in /etc/courier/imapd-ssl:

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