Tips for debugging a problem to connect to Sieve

[Andrés Tarallo]

I have two servers where I've deployed a Webmail (squirrelmail+avelsieve). 

One of them has direct conection to the sieve server, and works without
problem.

The other one is behind a firewall.The only thing we get when we do a
telnet is:
telnet THE.MAIL.SERVER 2000
Trying .THE.MAIL.SERVER  ..
Connected to THE.MAIL.SERVER .
Escape character is '^]'

Does sieve has any special requirments to go through a firewall?

A/P Andres Tarallo
WD&B Consultores
Montevideo - Uruguay