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Community Member

ATA 186 Registration From Behind A Firewall

I'm currently setting up Call Manager 3.1 & I have a question about device registration.

Right now, I'm using an ATA 186 for testing purposes. I have the firmware upgraded to so I can us SCCP & register with the call manager. I have everything set up on my local test network & all is fine.

I've previously been able to use the ATA to dial out & make calls through my Firewall via SIP.

In a few days, I'm going to be moving the Call Manager from the local test network to the outside. At that time, it will be necessary for my ATA registration to pass through the firewall on it's way to the call manager. I don't suspect that will be a problem because I do NAT on all outbound connections. The concern I have is with incoming calls from the call manager to the ATA & the port forwarding that will ensue. The firmware doesn't have SIP functionality, so how will that work? Will it work at all?

Surely someone out there is using these things behind a firewall.



Re: ATA 186 Registration From Behind A Firewall

Since there has been no response to your post, it appears to be either too complex or too rare an issue for other forum members to assist you. If you don't get a suitable response to your post, you may wish to review our resources at the online Technical Assistance Center ( or speak with a TAC engineer. You can open a TAC case online at

If anyone else in the forum has some advice, please reply to this thread.

Thank you for posting.

Community Member

Re: ATA 186 Registration From Behind A Firewall

on 2.13 there's support for SIP. Have you tried?

Community Member

Re: ATA 186 Registration From Behind A Firewall

Yes, I have tried 2.13. The problem with 2.13 was (unless I totally missed something) was that it didn't support SCCP.

I need to be able to do two things:

1. Route calls from an ATA behind a firewall to a Call Manager on the Internet. I can do this no problem with either 2.12 or 2.13.

2. I need to be able to register the ATA as a device on the call manager. So far, the only way I've found to do this is to use 2.12ms.

The problem I have is that 2.12ms doesn't appear to support SIP, which I need to get the ATA routed through the firewall. 2.12 or 2.13 doesn't appear to support SCCP, which I need to be able to register the ATA with the call manager.

So - I'm looking for anyone that has done this sort of thing before. What sort of working comprimise were you able to come up with?


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