I was unable to figure out Anveo Direct issues with NAT, actually. Even though it worked, it stopped working in a few minutes. I was told that it's because Anveo Direct doesn't proxy audio and underlying carriers do not play nice with NAT (even with STUN and port forwarding). I ended up moving Obi202 outside of the firewall and assigning it a real static IP, which fixed everything, but I doubt it will be an option for many.
Here is my relevant config right now:
I use SP4 as a proxy for my IP phone.
12121234567 - My phone number
000000 - Anveo Direct secret prefex
ITSP Profile D\General\X_SymmetricRTPEnable\ON
SP4\X_InboundCallRoute\{12121234567>(<011:000000>xx.)
VG1\Name\Anveo Direct
VG1\AccessNumber\sp4(sbc.anveo.com;ui=12121234567)
VG1\DigitMap\(<011:000000>xx.|<000000>xx.)
VG1\AuthUserID\12121234567
You need AuthUserID in VG1 or it won't work. You don't need a password. Naturally your static IP should be on the allowed list for your route plan with Anveo Direct.
Now that it's working, I like my setup. I have my IP phone proxied to Obi, from there all US/Canada calls are routed via GV (free), all international calls are routed via Anveo Direct and if I want calls recorded, I pay 10c and retail rates and route the calls via Anveo retail. Life is good.
Audio quality with Anveo Direct is great thus far. I tried US and a couple of international destinations, including cell phones and can't complain.