ZD sending Yahoo Mail

[rickvv]

In a corporate setting, we have our firewall pretty tight. We have port 25 outbound limited to just the Zimbra server static IP.

Zimbra Desktop doing Yahoomail works fine on incoming msgs, but not sending...

Do we need to allow outbound traffic on port 25 from machines that have ZDesktop running on Windows, and syncing Yahoo?
I have a user with 3 or 4 messages caught in ZD Outbox.

Firewall or nefarious captcha issue? (user noels57-at-yahoo.com)
firewall guy will not be happy

Would it work smoother if we used the Zimbra Web client? and not require port 25 from the workstatiion?

Thanks for help,
rickvv

[rickvv]

As an aside-
If i duplicate the user outside the business place (setup his Z, same build, same user, at my office), the Zimbra Desktop will send the yahoo message fine.
Plus I cannot get to his office Zdesktop til another three days to harvest the logs.
thanks,
rickvv

[rickvv]

Please, no one has advice on this Yahoo mail setting problem?