[Dovecot] BUG: Authentication client sent unknown handshake command

Hi everybody,

I'm using dovecot-2.2.11 on NetBSD.

After a kernel upgrade, while using the same dovecot binaries (they were working perfectly until today), I'm experiencing this error (more log at the end of my email):

BUG: Authentication client sent unknown handshake command: REQUEST?227672066?18807?2?c717631d60216b2e9ec57a2fa69674b8?session_pid=16343?...

I tried to build a newer version of dovecot (2.2.12) but same issue.

I know this should come from my system and not dovecot, but how can I debug this kind of problem ? I already enabled various debug (auth_verbose, auth_debug, mail_debug) but I need more information.

This issue have already been discussed on dovecot mailing list without solution :-)

Thank you very much.

Best, jym

Log:

Apr 16 16:29:16 dodo dovecot: imap-login: Debug: SSL: where=0x2002, ret=1: SSL negotiation finished successfully [::1] Apr 16 16:29:17 dodo dovecot: auth: Debug: client in: AUTH 2 PLAIN service=imap secured session=cE/PvSn3qgAAAAAAAAAAAAAAAAAAAAAB lip=::1 rip=::1 lport=993 rport=65450 resp=<hidden> Apr 16 16:29:17 dodo dovecot: auth: Debug: cache(mylogin@myhost.org,::1,): hit: <hidden> Apr 16 16:29:17 dodo dovecot: auth: Debug: client passdb out: OK 2 user=mylogin@myhost.org Apr 16 16:29:17 dodo dovecot: auth: Error: BUG: Authentication client sent unknown handshake command: REQUEST?227672066?18807?2?c717631d60216b2e9ec57a2fa69674b8?session_pid=16343?... Apr 16 16:29:17 dodo dovecot: imap: Error: Authentication server didn't send valid SPID as expected: MECH PLAIN plaintext Apr 16 16:29:17 dodo dovecot: imap: Error: Disconnected from auth server, aborting (client-pid=18807 client-id=2) Apr 16 16:29:17 dodo dovecot: imap-login: Internal login failure (pid=18807 id=2) (internal failure, 1 successful auths): user=mylogin@myhost.org, method=PLAIN, rip=::1, lip=::1, mpid=16343, TLS, session= Apr 16 16:29:17 dodo dovecot: imap-login: Debug: SSL alert: close notify [::1]