Multiple VOIPo boxes behind NAT

I run a small ISP and have my customers all NATed behind one public IP. I am testing VOIPo reseller service before rolling it out to my customers and running into problems with incoming calls going directly to voicemail or ringing but no audio or one way audio when answered.

I have read some forum posts that suggest forwarding a huge range of ports to the ATA. Obviously this will not work for my network configuration. Is it possible to get your service to work reliably without doing this?

I have been using HT286es with their default configuration. I do also have one VOIPo rt31P2 that I'm going to swap in tonight to test. I will also test assigning a public IP directly to the ATA to see if I can prove that it is the NAT causing the problem. I have tried turning on STUN using the voipo server, but that did not help.

I'm looking for any suggestions on how to get this working without having to allocate one public IP per ATA. I don't have enough IPs to do this in a production environment.

Also I should mention that if using VOIPo provisioned boxes will fix this, I am open to purchasing them from VOIPo. So let me know if that would fix it.

when I was talking to tim about this issue earlier and tim said that NAT should not be any problems.

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Originally Posted by timreichhart

when I was talking to tim about this issue earlier and tim said that NAT should not be any problems.

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It sounds like there would be a double NAT involved here at the very least.

ISP <-> NAT <-> CLIENT <-> NAT <-> VOIPo

@cfabe

If you have an example Call-ID (You can grab this Call Reference ID by clicking on Call From or Call To of the applicable call from Call History). I can further look into this and provide some possible insight as to the problem.

However with this kind of a NAT setup it is likely going to be a simple issue of blocked packets / traffic.

Hi guys,
There is no double NAT on my network. I have one mikrotik router doing NAT for the whole network. No customers are using their own routers, I supply some customers a router, but it does not NAT, it just routes.

PUBLIC IP <-> NAT <->BRIDGED WIRELSS NETWORK <-> VOIPo ATA

I guess I'm not sure whether the problems I am having are due to using the HT286s or my NAT/routing. I'm going to set up a couple boxes tonight to test over the weekend.

I'll install an HT286 with a real public IP. Then I'll also install your supplied RT31P2 on a private IP through NAT. We'll see which one works the best.

On my HT286 boxes should I be using STUN? When I tried once to enable that and point it at sip.viopwelcome.com it detected the right public IP but the call only had audio one way.

When I have any more failed calls, I'll make a note of the call ID. How should I best relay that information to the right person at VOIPo?

With Grandstreams, you might want to enable symmetric RTP, enable STUN, and enable random port under the SIP settings.

Having more than 1 device behind a NAT is a VERY tricky situation.

For more information on what's going on because of SIP and NAT not playing well together, I would recommend reading: http://www.voip-info.org/wiki/view/NAT+and+VOIP

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Having more than 1 device behind a NAT is a VERY tricky situation.

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Actually we have done this quite easily for over 5 years. Pretty much plug-n-play.. 6 numbers behind an Actiontec modem/router combo at the office with no changes to the devices or router to make them work.

I think a better way to say it would be is that it could be a tricky situation under certain circumstances...

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Originally Posted by chpalmer

I think a better way to say it would be is that it could be a tricky situation under certain circumstances...

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I think you're just lucky...

Extremely lucky.

More than 80% of the time people have more than 1 device behind NAT, they run into one way audio issues because the router doing the NAT doesn't know exactly how to handle the packets from other sources that the device isn't registered to.

Truthfully I think we only hear about the people that have trouble so seems that way.

Think of large corporations, school districts, fire departments, ect that have multiple locations and use ip phone systems. Ive seen many of these types of users with soho broadband routers in there "data closets".

With the right router heading up a network there should be no problem. But as stated here many times... Some routers try to do too much and cause problems.

One of the past providers for our office used separate servers for line one and two on the ata's. All ports were the same. Same port number for lines one and two. Think about that for a second... Same Linksys ATA's... Ive unlocked them now for our new provider...

I logged two calls that had problems today:

Call Reference ID: CXC-177-6595f7f0-a9d5ed0-13c4-4c547ae2-3e6fd247-50270900@208.94.157.10 - this call rang but no audio when answered

Call Reference ID: 72709d69b7abc98b@24.180.168.134 - this call was connected normally and dropped after about 2 minutes.

Thanks for any advice.