SSL23_GET_CLIENT_HELLO:unknown protocol

[Aki Tuomi]

> On 29/06/2021 07:50 Voytek Eymont <voytek at sbt.net.au> wrote:
> 
>  
> I have a user failing to get mail , using TBird client
> 
> is this due to his TBird email client backlevel TLS support ?
> 
> I'm trying to find out his TBird version, might be an older TBird
> 
> # dovecot --version
> 2.3.15 (0503334ab1)
> 
> # egrep "ssl_protocols|ssl_min_protocol" /etc/dovecot/conf.d/10-ssl.conf
> 
> #ssl_min_protocol = TLSv1.2
> 
> Jun 29 14:23:27 pop3-login: Info: Disconnected: Connection closed:
> SSL_accept() failed: error:140760FC:SSL
> routines:SSL23_GET_CLIENT_HELLO:unknown protocol (no auth attempts in 1
> secs): user=<>, rip= 111.222.333.555, lip=ser.ver.ip.add, TLS handshaking:
> SSL_accept() failed: error:140760FC:SSL
> routines:SSL23_GET_CLIENT_HELLO:unknown protocol,
> session=<kZ6p99/FW9iTMgHi>
> 
> 
> Jun 29 14:23:54 pop3-login: Info: Disconnected: Connection closed:
> SSL_accept() failed: error:140760FC:SSL
> routines:SSL23_GET_CLIENT_HELLO:unknown protocol (no auth attempts in 1
> secs): user=<>, rip= 111.222.333.555, lip=ser.ver.ip.add, TLS handshaking:
> SSL_accept() failed: error:140760FC:SSL
> routines:SSL23_GET_CLIENT_HELLO:unknown protocol,
> session=<Gq5G+d/Fu1STMgHi>

This seems like the client is trying to connect using STARTTLS to a SSL port. Or not using TLS at all.

Aki