From: DeskNow Knowledge Base
http://www.desknow.com/kb/

What ports does DeskNow use by default?
http://www.desknow.com/kb/idx/12/112/article/

This is a list of internet (TCP) ports used by the various services in DeskNow. All these ports can be changed in the various Administration pages.

SMTP 25
HTTP 80
POP3 110
IMAP4 143
HTTPS 443
SMTP SSL 465
IMAP SSL 993
POP3 SSL 995
XMPP 5222
XMPP SSL 5223