I experience this problem :
I use a Call Manager 6.1, a Pix 515 (PIX Firewall Version 6.3(5)), a c2821 and a 1751v Router.
The schema of the call is like this :
CCM6 <-> c2811 (dflt gw) <-> PIX <-> c2821 <-> 1751
In the LAN ther is Voice and Data VLAN with dot1Q.
The CCM and the c2811 and the IPPhone are in the voice Vlan. I use a 3750G-24T-S and an 3550-48-SMI
The link to the PIX is a trunk. Because there is 2 virtual interface on the pix(inside) : for the voice vlan, and for the Data VLAN.
The outside interface is connected to the 2821. This last is the VoIP gateway.
So the Trunk SIP is configured between the CCM6 and the c2821.
The 1751v is the distant agency that I want to call.
So the problem is like this :
1. If I let the PIX in its place, and change the CCM6 with a CCMExpress(another router), the call Pass
2. If I let the PIX in its place, and use the CCM6, the call don't pass.
3. When I change the PIX with a simple router, the call Pass, and it works fine.
What should be the cause?
I must use the PIX firewall.
Have you any issue?