Pi 3B+ no longer registering to Azure PBX v18

[KrisEiT]

Hi Guys,
This might be an obvious one but I needed to clarify whats going on and if its 100% the Pi at fault here.
We have an Azure hosted PBX for a customer who's using V18 of 3CX, we recently moved their office to a new location and after setting up the equipment the existing SBC re-registered to the PBX and phones worked as expected. about a day later we had complaints that the desk phones were no longer working and could not make calls, checking the PBX its showing the SBC as being offline. softphones are working as you'd expect, the only issue is with getting the SBC to register.

There's no firewall rules getting involved here or anything that would stop the Pi from being able to connect to the PBX from within the office, we've simply done a basic lift and shift to a new site with a new internet connection we've kept their exiting infrastructure , firewall, switches etc

We've got the SBC on our testing bench at a different site using a different ISP it boots up as expected, however I'm a little green with Linux so getting to a login prompt maybe a far stretch away from fully working and I appreciate this, so I've got a couple questions I was hoping you could help me with.

1. Are there any log files on the SBC I can look at that might give me an idea to what is going on and why it won't register ?
2. Is there a command i can run or file i can check to see the version of the SBC software to gauge if its so far out of date it won't work with the version 18 PBX anymore ?
3. Any other ideas on why it won't connect would be appreciated.
   
   
   I'm hoping this issue is limited to this SBC and not a compatibility issue from a recent update, since we have another 4 Pi 3B+'s at other remote offices for this customer that all appear to be working fine with no connectivity issues so far .

 

[CentrexJ]

You said at your testing bench it boots up ok. does it also register?

If so, likely at their new office you have an IP conflict where some other device is trying to use the same IP as your SBC/Pi.

 

[KrisEiT]

You said at your testing bench it boots up ok. does it also register?

If so, likely at their new office you have an IP conflict where some other device is trying to use the same IP as your SBC/Pi.

Hi, sorry meant to mention the unit failed to register on our test bench as well, it just boots up and sits at the login prompt to linux, and regardless of how long its left the PBX never shows it coming online.

With regards to a DHCP conflict the unit when its on the customers site is set with a static address that's part of a range of IP addresses that are specifically outside of the DHCP range to avoid any issues with conflicts.e.g.

the pi would be on 10.0.0.10 and the dhcp range starts at 100 - 254, when its at our site its on a test network and isolated from anything else so its essentially the only IP on the network outside of the upstream router for internet access.

 

[CentrexJ]

I would wipe the SD card and re-configure it from scratch.

 

[pmterp]

@KrisEiT as others have mentioned, it would probably be worth re-imaging the SD card and starting over,
If you'd rather poke around a bit first, log in to the unit and check the DNS settings. I've seen multiple cases where old DNS settings were not automatically updated when moved to a new network.
you can run

cat /etc/resolv.conf

to see the current DNS servers and if needed,

sudo nano /etc/resolv.conf

to edit them. Reboot after making any changes and see what you get.
There are also logs you can check but it would probably be easier to re-image than go that route. If you want to dig into the logs, some searches should point you to them but if not, reply and I/others can provide more specific instructions.

 

[KrisEiT]

@pmterp @CentrexJ Is it still possible to re-image a Pi3 since the 3CX setup / build now seems to say its for the Pi4 ? I'd avoided doing this since I don't have a Pi4 to rebuild onto and can't find anything that says it will work with the 3's anymore.

If its not possible to rebuild the 3 we'd need to talk with the customer about purchasing a new unit before we rebuild.

Thanks for the help & replies

 

[CentrexJ]

@pmterp @CentrexJ Is it still possible to re-image a Pi3 since the 3CX setup / build now seems to say its for the Pi4 ? I'd avoided doing this since I don't have a Pi4 to rebuild onto and can't find anything that says it will work with the 3's anymore.

If its not possible to rebuild the 3 we'd need to talk with the customer about purchasing a new unit before we rebuild.

Thanks for the help & replies

You are good to rebuild using the 3CX Pi4 instructions.

 

[pmterp]

As @CentrexJ said, the current available instructions will work for the Pi3. If you're worried about it, use a different SD card and try it out. If it doesn't work for some reason, you can always pop the old one back in and then dig through logs (but it shouldn't be necessary).

 

[KrisEiT]

@pmterp @CentrexJ just wanted to say thanks for the advice, we've rebuild the Pi using the latest image and its all good to go again.