We run an I3 EIC IP PABX on Windows 2003 with dual NIC’s, NIC1 is for data NIC2 is for VoIP. Default Gateway is set on NIC1.
NIC1 DATA : 10.0.1.13
NIC2 VOICE: 10.0.1.14
Gateway : 10.0.1.1
Issue: 3 of 10 remote sites began having one way voice. I discovered that the RTP for the audio was generated and dynamically allocated ports on NIC2 IP address but was being sent from NIC1 and the handset was returning traffic to NIC1 IP which did not have the dynamic ports allocated or opened which obviuosly resulted in the one-way voice. As a temporary measure I have moved the gateway over to the NIC2 but the implication is degraded voice quality as DATA and VOICE packets converge on a single NIC.
Given that this is only happening at 3 sites what could be the issue? What could be done to permanently resolve this?