[asterisk-users] Re: OK to have Asterisk and clients behind firewalls?

[randulo]

> So... I guess it's something in the 3102 that must be changed so that
> it will finally TX/RX voice packets to remote phones (works fine when
> picking up an IP phone in the same LAN as the 3102 and Asterisk).

Here's something from an old post:

Upon replacement of the Linksys, everything worked fine except audio
on the Sipura. Turns out you need Symmetric RTP turned on in the phone
as Chris Mason says below.

See if those settings help? And join the Asterisk Users Conference and
ask the question there or go to the IRC #asterisk channel. Someone
there may have the same phone.