Had similar prob - faxes would work internally but not from external. Main gateway is a 3825 with fax machines hanging off VG224. Turns out that on the 3825 I had set mgcp bind to a loopback rather than to a routable interface. Interface g0/1 was on ...
Same as rest - even though CUCM Publisher said NTP servers were fine, subscriber wouldn't accept. Finally had to put in NTP server of the 4510-e switch that VMWare/bare metal box was directly connected to and wait five minutes - then it went throgh ...
