a) a linksys pap2 with two lines configured in mini-pbx mode. Both online per pap2
b) two pots lines
c) google voice configured with all the above to ring on incoming calls.
Outgoing calls work fine. Incoming calls fail to ring intermittently (approx50%) on the two linksys lines and never fail on the Pots lines. Google voice settings remain the same between working incoming calls and non working incoming calls.
Any help appreciated!
Setting the registration timer lower, enabling NAT Keepalive, or using SIP over TCP should help solve problems like this, usually caused by your NAT router blocking the incoming call connection.
If I am not mistaken you use DNS_SRV records and doesn't this mean that his ATA may be rejecting a call that is not coming from the IP e registered to? He should not restrict calls to the proxy address and enable DNS_SRV.