Incoming Calls rings once then hangs up

I inherited a VOIP system at one of my clients. I have limited experience with VOIP and FreePBX. It had a failing Asterisk NOW PBX server. The SIP trunk comes in on a dedicated line from their ISP through an ESBC 9378-4b Session Border Controller. I have replaced the old PBX with a new Sangoma 40 PBX. I have setup the trunk and in/out routes, extensions, IVR… etc.
I have several issues:

  1. The trunk says it’s online. However, when I dial the main DID it rings once then hangs up.

  2. The original system had the phones on a VLAN 100. The old server had eth0 set to and eth1 was set to When I came on the scene eth1 was not plugged in. So I don’t know how the Digium D70 phones were getting their config. I tried adding a second interface on the Sangoma for the 192.168.100.x network and when I did I lost DNS resolution and internet access and I could not access the web GUI. Not sure where to go here. How do I get the phones to connect to the PBX if I can’t get a connection to the VLAN. Can I create a VLAN interface on the same port. of the Sangoma PBX.

  3. The last thing I notice is that the Router onsite did not have a VLAN 100 setup on it so I suspect whoever set the old system up was just setting static IPs on everything.

/var/log/asterisk/full will give you the info on what’s happening on the PBX. If the calls aren’t making it there, it’s the SBC that’s killing you.

People love their VLANs - I don’t get it. The broadcast domains for most of these network is so small that adding the complexity and overhead of a VLAN just doesn’t make sense to me.

This sounds like a problem you need to solve in the underlying operating system. I recall that there are problems with routing when you use the GUI to add new interfaces - the default routing gets messed up and you end up with problems like you are describing. Of course, VLAN interference can also figure prominently in this calculus, so you might need to tune that as well.

It sounds to me like whoever set it up didn’t want the phones communicating off-site, which is probably a good thing. You can accomplish similar results by using different LAN definitions (without the VLANs) and allowing the devices to communicate over the LAN using both ‘networks’.

Yeah, I agree!!! 10 phones, 10 workstations, a server and a few printers. All on Gigabit LAN. I don’t think they have any traffic congestion issues.

I’m interested in this idea. Please elaborate.

Yeah, that’s what I was thinking too. The unfortunate part is the ISP no longer provides tech support for that VOIP system. It’s just still running because they had a 5 year contract???WTF. Second, I have no idea what the login creds to the SBC are and the person that set it up has disappeared from the face of the earth. Lastly if I default the SBC, I cant get the SIP authentication info between the SBC and the ISP. They don’t have it anymore. I’m in a real pickle. I was hoping I could just match the config from the old PBX and I’d be in but there must be some identifier in the SBC such as a MAC or something.

Simplified things! I was also able to get the correct Sip trunk info I needed from the ISP finally. I’m all good now. Thanks for your input cynjut!

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