Can't talk to IP Phone on other side of NAT device??? 1

[jonnyGURU]

I used the search function (Yeah!!!) and found this:

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You cannot put a hardphone behind a NAT box without VPN tunnels.

IP Hardphones embed their local IP address deep within the h.323 packet, and the 412 will try to respond to that ip address not the public NAT address of your home 4606 users gateway. Regardless of what the packet header has to say on the subject.

To do what you want, both ends must operate in non-NAT mode (sometimes referred to as router mode vs. gateway mode), and you must have multiple public IP's, even for the home users.

Peter
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Say it aint so! I'm trying to get an IP Phone to work on the other side of a NAT device. I can get to the IP Office (the TFTP initiates) and apparently the IP Office can't get back to the IP Phone.

I figured if the IP Office is really a Layer 3 router, it should be able to do this!

Obviously, I can throw an SG on the IP Phone end of the equation and build a VPN tunnel, but the salesperson didn't sell an SG and I didn't have the foresight to think that it WOULDN'T work (there I go not thinking like Avaya again.) Also, if the IP Phone has it's own public IP it works too, but they only have the one IP. The traffic has to go through the customer's router.

Can anyone help?

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[Morrack]

Sorry, but it really is so. I spent a good deal of time on this very issue last year. NAT and h.323 do not go together on IPO.

Peter

 

[jonnyGURU]

Oh? I think I'm going to cry.

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[JeSTeROCK]

Avaya should have a look at what other manufacturers are doing with H323

For instance samsung can get passed this by having a public and private ip address on the ip phone and the same on the ipoffice side. You can then port map on the routers. Works very over the internet without VPN!

 

[Morrack]

If you want to pay for multiple static IP addresses at each location you can forgo the VPN and turn off NAT and IPO will work fine. I've done this. However, not all routers are capable of turning NAT off. I used Linksys (a division of the big C) BEFSR81's for the home users, as they support QoS.

Peter

 

[jonnyGURU]

Right... but for the long term, if they're going to pay for multiple IP's, they might as well pay for a VPN gateway. And since the ball is in "our" court and we're not paying for the ISP, looks like we might end up springing for an SG.

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[Morrack]

Except that if you aren't worried about securing your conversations (which you clearly aren't if you were going to use port mapping instead of a VPN) you will get FAR better voice quality without the VPN.

But I do see your point

Peter

 

[bazlit]

does Avaya have any SIP capabilities? does it suffer the same issues as H.323?

 

[jonnyGURU]

I think last year they came out with firmware that made their phones SIP compatible, but the IP Office itself is not SIP compatible.

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