Different routers are used to connect to the internet, these routers often work fine but sometimes we see issues when certain routers are used.
In the list below we will try to document issues we found during installations.
Netgear WNDR3700, no incoming speech. RTP stream is blocked by the router.
Login the router using the web-interface: Go to Advanced - WAN Setup and Disable the SIP ALG by activating the check-box.
Some VoIP applications do not work well with the SIP ALG. Enabling this option to turn off the SIP ALG may help your VoIP
devices to create/accept a call through the router.
AVM Fritz!Box Fon WLAN routers, incoming call not possible.
A general problem with routers that also has a VoIP client in the device is, that the port 5060 is used by the router for the integrated VoIP client. Incoming invites from the provider are send to port 5060 and instead of forwarding the calls to the PBX, the router will accept the invite. We suggest not to use the AVM router in combination with the Gigaset PRO T300/T500, this because you are not allowed to forward port 5060. Some internet providers have made a special configuration, if this is the case than the router can be used.