NAT Setup - No inbound calls

[uf_shane]

When you put a Mac Addy into the DMZ, all traffic restrictions are bypassed... meaning the internet is given 100% access to that device.

[tritch]

Attaching more than 1 SIP device behind the same router can cause problems. Basically, you are trying to route SIP traffic from 1 public IP going to your router's WAN to 2 private IP's (Grandstream and Cisco 7960) on your router's LAN. The first thing you want to make sure of is that each SIP device is using a different SIP port. In other words, you want to make sure that the 5060 port is not already being used by either of the Grandstream registered ports. In vPanel under registered devices, look to see if the Grandstream is using 5060 already. If so, change the Cisco device to use something else, like 5079.

Also, do you have any type of port range forwarding in your router for the Grandstream device? If so, remove it. This will cause the inbound calls to work for the Grandstream and fail for the Cisco device because the router will only forward the call traffic to the Grandstream. Likewise, don't use any type of port range forwarding for the Cisco device either or inbound calls to the Grandstream device may begin to fail as well. Bottom line, if you connect more than 1 SIP device behind the same router (where call traffic needs to be routed to different private IP's), you are asking for trouble using port range forwarding for either device.

With all port range forwarding turned off and making sure each device is using a different SIP port, things will likely work......