PAP2 Voip box with VM Ambit box

Frank_999 · 12-04-2009, 13:50

Hi,
I am a VM Cable Broadband Customer with the smallest broadband package, I have my own Netgear WGR614 v6 hub plugged into the one port on the back of the VM supplied Ambit (Model no: E08L013.00) modem/router.
I am having 'double' natting issues with a Linksys PAP2 VOIP box and Gradwell VOIP services, this box is plugged into one of the Netgear Hubs RJ45's ports.
Until I find a way to avoid the double natting I cannot use a 3rd party VOIP with the PAP2.

I have called VM help but they will not offer support beyond their Ambit box, and will not give me any clues on how to login and configure their Ambit box.

Anyone had this issue and found a solution.
Thanks Frank.

KingDaveRa · 12-04-2009, 14:39

AFAIK, the ambit doesn't NAT, it just routes across the connection (or possibly bridges).

What's the problem you're having? I'm guessing you're getting silent calls or something, as SIP has a world of ports to open, depending on which codec it's using and what it's trying to do.

Ignitionnet · 12-04-2009, 16:25

The Ambit is not a router, it's purely a bridge, and will only accept having one device plugged into it. You should be fine just with the PAP2 directly into the modem then everything else behind it. If you have anything else plugged into the hub this will break things, you must only have one single device (apart from a switch or hub) plugged into the Ambit modem at one time.

Code:

LAN --- PAP2 --- Ambit = ok

PAP2 ---  |
        Hub --- Ambit = not ok
Router --|

KingDaveRa · 13-04-2009, 09:42

See, the thing that confused me recently, was with a colleague trying to do something. We were testing some video conferencing stuff from Tandberg, and he had one of the units at home. To make life easier, I told him to plug it directly to his modem (he's on 50Mb). He said it was reporting an IP of 192.168.100.10, which confused me a bit, as I thought it should have picked up a fully routed IP, like the router does. It's not outside the bounds of reality to do that, and have a routed hop using statics, but still, it would counter to what I'd seen, as as far as I was aware, the Ambits just bridged. Perhaps the newer ones do something extra too.

Ignitionnet · 13-04-2009, 10:39

More likely he didn't restart the modem in between switching the devices so the network refused to give the Tandberg an IP address as you're only allowed one device connected to the modem at once. Where a device can't get an IP lease from the network the Ambits do contain an internal DHCP server which gives out very short leases in the 192.168.100 / 24 range to allow you to access their management pages.

caph · 13-04-2009, 14:01

Frank, check that you are using your VOIP provider's domain proxy. The proxy is used to work around any NAT problems.

Kymmy · 13-04-2009, 14:39

A business line will allow you to go

AMBIT
<>HUB/SWITCH
<>ROUTER<>VOIP

but not the residential line, other than that what about the DMZ on your router???

KingDaveRa · 13-04-2009, 19:20

Quote:

Originally Posted by Broadbandings

More likely he didn't restart the modem in between switching the devices so the network refused to give the Tandberg an IP address as you're only allowed one device connected to the modem at once. Where a device can't get an IP lease from the network the Ambits do contain an internal DHCP server which gives out very short leases in the 192.168.100 / 24 range to allow you to access their management pages.

First off, it got no IP, so I told him to reboot the modem, then Tandberg. It got an IP, being the private one. I told him to try a call anyway, fully expecting it to fail, and it connected, and we held a video call fine.

I can only assume the Tandberg was having a bit of a magic moment. I'm planning on bringing it home myself to try, and see what happens here. I think I'll put it down to 'one of those things'.

Ignitionnet · 13-04-2009, 22:01

Quote:

Originally Posted by KingDaveRa

First off, it got no IP, so I told him to reboot the modem, then Tandberg. It got an IP, being the private one. I told him to try a call anyway, fully expecting it to fail, and it connected, and we held a video call fine.

I can only assume the Tandberg was having a bit of a magic moment. I'm planning on bringing it home myself to try, and see what happens here. I think I'll put it down to 'one of those things'.

No, it was most likely the two having a scrap over which gets to the modem first and gets the public IP address, you cannot have two layer 3 devices on the same layer 2 segment as the modem and expect it to work normally - it won't

Whatever gets to put the DHCP request through the modem first and gets the public IP address will work, the other either will get nothing or the 192.168.100/24 address as above.

The devices will have to be connected in series.