SMTP protocol violation: synchronization error
|Reported by:||rinnes||Owned by:|
Unable to send mail through roundcube when SSL is enabled over Exim4. Exim is working correctly as I have manually connected and authorised with it and also connected using 3rd party client software and can authenticate and send mail fine.
When sending mail through Roundcube the following error is reported in Exim's 'rejectlog'
2008-02-20 22:13:48 SMTP protocol violation: synchronization error (input sent without waiting for greeting): rejected connection from H=rubix.xxx.com [xx.xxx.xx.x]
Basically, Exim will deny the message if the session sends data before the SMTP banner or if remote client sends data out of sync.
This is caused by Exim being more compliant to the SMTP RFC, it will drop the connection if this results.
I'm guessing that this can be fixed by ensuring Exim has sent its response to the smtp greeting before continuing with the authentication process.