Testing VoIP

Posts: 3 · New Forum Member Joined: Apr 12, 2006 Posts: 3

I am going nuts here and my wife is about to throw Vonage out the window!

I am trying to troubleshoot our constant dropped calls, and one-sided silence. I have a Com-21 cable modem using Charter high-speed and get good results on the normal broadband tests. I have a PAP2 phone adapter and a WRT54GL router with the QoS firmware upgrade.

However, whenever I try to run a Voip speed test (testyourvoip.com), It tells me that it cannot connect, or that my adapter may be blocking those ports.

I've now tried to run the tests on a Fedora Core 5 system and a Core 4 system.

I have tried turing off all firewall options in the operating system AND the router! I've even tried just connecting my computer to my old SMC barricade router so that just the cable-modem and my computer were connected!

I am not able to run any sort of Voip testing for some unknown reason!!! Has anyone else come across this and have a solution???

Thank you!
Brent

Posts: 2257 · Posted: Wed Apr 12, 2006 6:42 am Post subject:

Hmm. If you have disabled all of the firewalls on your end, it sounds like your ISP might *possibly* be blocking Voip ports.

What you might want to do, since you have the WRT54GL, is do a trace on the connection attempt.

Get a package like "WallWatcher" (sorry, I use Windows and I don't know what the Linux equivalent would be offhand - you want a syslog daemon monitoring package that can receive UDP firewall notifications), and set the WRT54GL to send everything to it. You can then watch the connection attempt to testyourvoip.com and see if the messages reveal anything useful.

You don't, by any chance, have port forwarding set up in any of your equipment, right?

Does testyourvoip.com fall back to port 6000 or does it fail completely?

Posts: 3 · New Forum Member Joined: Apr 12, 2006 Posts: 3

Thanks for the ideas!

If my ISP was blocking all Voip traffic, my phone shouldn't work at all. This is what is so frustrating! We have phone service, but it just has a lot of problems with dropping calls and periods of silence on one end or the other.

I had used a tool, I think it was called "sip_ping" that showed me that I could get out on port 5060 and 6000. However, the testyourvoip.com tests (on 5060 and 6000) would still fail.

I have noticed that the new firmware upgrade is a little different than the howto page that you have up, but I thank you for putting those pages up!

I have my QoS stuff setup correctly, and whenever I do a normal bandwidth test I have plenty of bandwidth available.

I am at the point where I can either try to buy a newer cable modem (like the roadrunner) and see if that fixes things, or I am going to just bail and pay twice the money every month for phone service that is reliable.

Thanks for your reply. If you have any other ideas or advice, I am definitely open to hear it!

Brent

Posts: 2257 · Posted: Thu Apr 13, 2006 7:47 am Post subject:

Well, remember, the blocking may not actually be done via the port numbers. They might have implemented L7 filters, or content filters.

You are correct, though, a block of Voip data would most certainly kill Vonage completely, so Vonage would not work at all under those circumstances. On the other hand, though Vonage uses standard SIP/RTP, they may be employing it slightly differently and it might confuse or misdirect the filters.

What DOCSIS revision does your COM-21 support? Whenever I see oddball modem brand names, I immediately get suspicious. Wink

Please note that I am not willing to blame everything on old DOCSIS revisions, since I am most happy with my DOCSIS 1.0 Linksys modem, but of course Linksys makes good gear.

Posts: 3 · New Forum Member Joined: Apr 12, 2006 Posts: 3

First off, I want to tell you that I really appreciate the time you spend answering people on this forum!

I was doing more checking today, and my Com21 modem (Model: DP 111) is only DOCSIS 1.0 compliant, and the Vonage site recommends upgrading.

I figured that I had nothing to lose and bought a SURFboard SB5120 on the way home from work. If it doesn't help, then I'll return it.

I had my teenage daughter put the phone through rigorous testing tonight! And, she did not have ANY problems! And this was over a period of 3+ hours of continuous testing!

I am not going to say everything is 100% perfect yet, but things are looking very good right now.

Being the geek that I am, buying a new router and cable modem was nice for me. However, this whole process seemed to be much harder than it should have been.

I'll come back in a few days and let you know if this has finally solved all of the problems that I've been having.

Thank you again!
Brent