We have seen a few questions about connecting to Comcast.net email from Zimbra Desktop. So I thought I'd post settings I found that worked. I tested these with Zimbra Desktop 2.0 Beta 3.
Account Type: POP
Receiving Mail Settings
User Name: email@example.com
Incoming Server: mail.comcast.net
Sending Mail Settings
SMTP Server: smtp.comcast.net
Edit the Port to "465"
Check the "Use SSL encryption when sending mail"
Check the "Username and password required to send mail"
User Name: yourname
Check the "New messages" box to "Leave on Server"