dovecot - Jun 2011 - Waiting for authentication process to respond..

Hmm... I'm seeing a lot of:

 > * OK Waiting for authentication process to respond..
 > * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE 
IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN AUTH=GSSAPI AUTH=GSS-SPNEGO] Welcome 
to the IFM Dovecot Mail Server.

when IMAP clients connect to our server (ie that "Waiting for.."
message
before the login OK message).

Now, most clients seems to handle this extra information message just 
fine, but it still is annoying me. It doesn't appear all the time, but
pretty often...

What can I adjust/fix in order to make it go away?

System:

Sun Fire X4240, 32GB RAM, 2 Quad-Core Opteron 2356
Solaris 10 Update 9
Dovecot 2.0.13
Maildir on local (ZFS) storage

Normally about 200-300 unique users connected, around 400-600 mail 
processes.
-- 
Peter Eriksson <peter at ifm.liu.se>   Phone: +46-705-18 27 86
Computer Systems Manager, IFM, Link?ping University, Sweden

On Wed, 2011-06-15 at 14:40 +0200, Peter Eriksson wrote:
> Hmm... I'm seeing a lot of:
> 
>  > * OK Waiting for authentication process to respond..
>  > * OK [CAPABILITY IMAP4rev1 LITERAL+ SASL-IR LOGIN-REFERRALS ID ENABLE
> IDLE STARTTLS AUTH=PLAIN AUTH=LOGIN AUTH=GSSAPI AUTH=GSS-SPNEGO] Welcome 
> to the IFM Dovecot Mail Server.
> 
> when IMAP clients connect to our server (ie that "Waiting for.."
message
> before the login OK message).
> 
> Now, most clients seems to handle this extra information message just 
> fine, but it still is annoying me. It doesn't appear all the time, but
> pretty often...
> 
> What can I adjust/fix in order to make it go away?
I'd guess it means two things:

1) Client doesn't actually care about the OK reply at all, and tries to
send some command immediately after connecting.

2) You're using the "high-security mode" of login processes, which
is
why there is a small delay before login process gets a reply from auth.
You could switch to either "high-performance
mode" (http://wiki2.dovecot.org/LoginProcess) or probably just setting
service imap-login { process_min_avail } to some small number also
helps.