searching for a 25 seconds delay

[Iv Ray]

Hello everyone,

For several months I have been searching the reason for a 25 seconds  
delay on every Squirrelmail operation (login, select folder, select  
another page) - the mail server runs on FreeBSD 6.x with latest  
postfix and Cyrus IMAP with Cyrus SASL authentication against a  
PostgreSQL database.

Mail clients like Mac Mail, Thunderbird, etc. do not exhibit this  
problem.

I received some guidance on this list and I tried quite a few things  
without being able to locate the problem.

Today, however, I finally noticed something -

1. All operations that I could try using imtest respond immediately  
(including initial login).

2. However the initial login of cyradm is delayed exactly 25 seconds.

It would be great if someone could help me analyze the reason for this  
difference, which might bring me closer to the issue.

Cyrus does not have redundant authentication mechanisms (some people  
suggested that this might cause delay) and the 25 seconds appear very  
stable (i. e. it is always 25 seconds).

Thank you very much!
Iv