Router problems while using the FPL softphone

[vincent_zalzal]

Hi,

I'm thinking about switching to FPL using an ATA eventually, but before that, I want to test that everything works using the softphone with my ISP (TekSavvy cable in Montreal, so really it is Videotron). I encountered way more problems than I was expecting, on the router side. Right now, I'm kind of stumped, so I want to know if any of you have some ideas. Here is what I tried:

Current setup: PC -> TrendNET TEW-639GR v1.0 router -> DCM-475 cable modem

I forwarded the following ports using the "gaming" page:
- 5060-5061, 6060-6061, 13000-13001, both TCP and UDP

I used PortForward Network Utilities to confirm that the router has indeed opened the ports.

When I try to use FPL softphone, I cannot call anyone and I cannot receive any call. When I use the "Test connection" option, it times out. I used TCP View to look at the port activity. When I try to call, I see packets (incoming and outgoing) on port 6060, but nothing else. When I try to receive a call, nothing happens.

I tried using DMZ instead of port forwarding, but it didn't work. I updated the router to the latest firmware revision. I also tried a factory reset, to no avail. I also tried rebooting the cable modem and the router.

Second setup: PC -> Linksys WRT55AG ver.2 -> DCM-475 cable modem

This went a little better, even if the router is way older. I forwarded the same ports as above and confirmed it using PortForward.

Now I can send and receive calls. I see ports 13000 and 13001 open when the call starts. However, there is one problem: when I am the caller, I can be heard, but I cannot hear the callee. The weird thing is, if I am receiving a call, then the audio is OK in both direction.

I tried using DMZ instead of port forwarding, but it didn't work.

Third setup: PC -> no router! -> DCM-475 cable modem

In that case, everything works fine.

Any ideas? I really don't understand. It is as if the routers are filtering some SIP packets or something. Anyway, do you think I would have the same problem using an ATA instead of the softphone? Because ultimately, if it works using the ATA, I'm happy. I don't care about the softphone. It's just that I don't want to pay 50$ for nothing. Maybe the solution is simply to buy a better router.

Thanks for the help.

[bridonca]

The TEW-639GR is a real stinker of a router! It is uses an poorly supported realtek chipset, and Trendnet is not exactly known for supporting their gear. I would work on replacing that router if I wanted to work with SIP VOIP. I strongly recommend you find a new router that is able to support a 3rd party firmware like DD-WRT.

[vincent_zalzal]

I wanted to give potential readers an update.

I bought a Linksys E1200. It is a fairly priced wireless-N router, and it is well supported by dd-wrt. The official firmware is also somewhat VoIP- and QoS-aware. I tried it out-of-the-box, without any port forwarding, with the official firmware and the FPL softphone worked flawlessly.

Next, I bought the VoIP unlock and configured my ATA. However, I got the uni-directional audio problem again. Port forwarding and DMZ did nothing to solve this. Then, I enabled SIP ALG in the router. This option seems to cause problems to many people, but it solved mine. The E1200 with SIP ALG works without any port forwarding with my ATA (Grandstream HT-502). So, all is well. And if I ever have problems with the router, I can flash it with dd-wrt.