Registration packets are not getting out but options are

Asterisk Asterisk Support
1

Asterisk was working really good here and then something changed. The problem went away by itself but now it’s back.

Here’s my problem and I am really stuck and stumped as to why this is a problem. It’s going to get a little technical.

I took my entire system over to another location and confirmed that it was working OK, all packets get sent and REGISTRATION happens OK and all that, calls go out etc…

For some reason I can’t register anymore with the SIP provider. It’s only REGISTRATION packets that have a problem.

I recorded packets using tcpdump at both locations so I could compare a good registration vs. a bad one.

Everything is the same (except the outside IP) the IPs for the provider are correct and the same.

When it’s bad - I see a OPTIONS packet go out and a OK packet comes back from the provider at the SAME IP and port 5060 as the REGISTRATION packets just like it does at the good location. So I know the NAT routing is working and allows the UDP packets back to the originating computer.

The next thing that is sent is REGISTRATION, and nothing comes back! At the good location, it registers and sends a final OK at the end like it should.

I don’t know what changed, but everything is open on all the routers, no firewall blocking, and when you think about it, if port 5060 was blocked, why do I get back the OPTION “OK” packet from the server?

Remember, this is not a password problem, I don’t think the packet ever gets to the SIP provider or somehow it doesn’t get back to this computer. Minimum I should get a un-authorized or something from the SIP provider if it was something like a password problem, or even a format problem in the packet, NOTHING comes back like the server never gets the REGISTRATION packet.

This is very strange and I don’t understand why. All other stuff like web browsing works, doing ssh etc… And I also tried using a program called “Ekiga” which is a program based SIP call program and it has the same registration problem even with the Ekiga SIP servers! So it’s not the SIP provider in particular.

The only thing that would do this is possibly a “stateful” packet filter that sees REGISTRATION and blocks it. Which my ISP shouldn’t be doing because they allow VOIP such as magic jack etc…

Any ideas? I’m stuck!

2

Did you do the checks on the Asterisk CLI via “sip set debug on” command?

I think a lot of things point to the router acting up and blocking some requests. You can proove that by doing some packet sniffing on correct parts of your network.

3

[quote=“dejanst”]Did you do the checks on the Asterisk CLI via “sip set debug on” command?

I think a lot of things point to the router acting up and blocking some requests. You can proove that by doing some packet sniffing on correct parts of your network.[/quote]Yes of course, I also watched the packets with tcpdump (like wire shark but command line).

I checked everything I could get access to, if something is blocking it would be on the ISP side which I don’t have access to, but they should not be blocking anything.

Most of the more simple blocks are port based and I am getting OPTIONS packets to go both ways no problem on port 5060.

Thanks for the suggestions.