sundance-communications.com/forum Forums TDM Business Telephone Systems Toshiba Telephones & Systems COMCAST Cable Blocking VOIP?

We have an employee in Florida who is having difficulty getting her Toshiba IPT-2020 connected to our phone system in California.

We've been told that her Comcast service may be blocking the VOIP. Does anyone know if this is true or not?

Another tech stated that the router was the issue. She has a Linksys WRTxxx I have her purchasing a Netgear FVG318 today to test the theory.

Any help would be great!

I've had problems with that particular model wr54t or something like that. I haven't tried the Netgear yet but turn off SPI if it has it.

I know that Comcast is not blocking VOIP here in VA, in fact we use it quite a lot. We did have some problems with the original Linksys routers we were using, but lately we have been using D-Link #DIR-625 units and haven't had any trouble at all.

I will add that this happened quite by mistake. The end-user had a Linksys unit that they picked up at Best Buy and had nothing but trouble with it. She took it back to get a replacement unit, but the store was sold out. They told her to just go pick out another one in the same price range, so she got the D-link one. When I heard how well it worked, I did the same thing with mine at home. It turns out that Best Buy had dropped the Linksys units due to a high out-of-box failure rate.

Toshiba knows about the problem with the Linsys wireless routers. They have SPI firewall built into ver 4 or 5 and newer. Unlike Netgear, the Linksys SPI firewall cannot be turned off.

As noted, if you get a Netgear, disable SPI firewall.

The netgear has a funny way of firewalling things. They are called rules and services.

I can't find anything specific to SPI...

Anyway, we tested the theory this evening with a netgear and still have the same problem. The only thing that has not been swapped out yet is the ISP... At this point we have SBC scheduled to install DSL on Wednesday... Hopefully that will be the end of the nightmare!

I think it wont be long before we see isps and/or the government start blocking voip traffic...

it is a conflict of interest for them..

its the wild west right now.. enjoy it while it lasts !

Here is the update...

COMCAST does block VOIP... Yet, they will not come out and say it. The entire configuration has been replaced... Every phone, every router and each modem... Nothing changed UNTIL we switched to AT&T DSL... Yes, it is a downgrade in speed - but at least it works.

As for COMCAST, here is the article to nail the coffin shut. ( https://www.spectrum.ieee.org/oct05/1846 )

After reading the article, my main question would be "Why do you own a piece of software whose sole purpose is to block VOIP packets?" And my second question is, "why don't you have the balls to tell customers homemade VIOP or Vonage will not work on your network?" Why do you have your support reps reading statements that some attorney's wrote.

Scummy if you ask me... Real scummy... Comcast had six phones calls to tell us that it wouldn't work - that they were intentionally blocking the packates... But no, each time we asked a direct question - they indirectly answered it. Get some balls comcast!

While on the topic - we also have discovered that the Netgear FVG318 will not work with the Toshiba equipment/setup. We are having success with the following two routers...2Wire and Netopia. We did experience successful tests with some Linksys models as well.

And the RIAA shut down Napter and thought that online music sharing would stop. VoIP is not going away. I don't think blocking this type of technology will help them in the future. Most people don't like restictions on their Internet connection.

I have several IP phones deployed in the field, and they span Charter, Comcast, and Quest DSL.

Linksys WRT54GL routers can be configured with 3rd party firmware from www.dd-wrt.com, which provides QOS support. Punch in the MAC address of the IP phone, and it really smooths out jitter.

One problem I had was keeping our BIPU firewalled "just enough" without opening it to the entire Internet, and permitting in-house IP phones to work with the same IP address. BIPUs can't be NATted: you have to have a public IP, or be on a VPN.

To determine if the Linksys router is the problem on the IPT phone end, simply plug the cable modem directly into the IPT WAN (Internet?) port and power cycle the modem and phone.