Solved Slave Bridge PBX can't see presence of just 1 location

[johnporteous]

Hi All,
I have a weird situation that arose this weekend when I migrated an existing PBX to a new server and changed the OS.

In this issue, there are 3 self hosted PBXs, geographically spread. Prior to the migration (done a restore on the new VM & OS and worked a charm), all 3 PBXs could see the presence of one another and call with zero issues.

Here is how I have it configured (when I say 'can see' I mean extensions are listed in the phonebook etc).

PBX A - Is Master to PBX B and Master to PBX C. Can call and see both B and C
PBX B - Is Slave to PBX A and Master to PBX C. Can call and see both A and C
PBC C - Is Slave to PBX A and Slave to PBX B. Can call both A and B; can see PBX B....BUT Cannot see A.

That is the issue; PBX C cannot see PBX A.

When I restored, I simply changed the IP of the Bridge where required but it didn't seem to like it so I deleted all Master and Slaves between the 3 and started again. In fact I have done it several times, methodically going through settings to ensure I had missed any, done side by side comparisons of settings for the same reason. Everything appears to be exactly set correct, just the presence won't work.

The firewall passes tests, no issues making outbound calls, rules are correct as tested calling between all PBXs.

I had this issue a couple of months ago and it was cleared by simply adding :443 once. This time around as it's a migration, as part of the new install from 3CX you have to nominate the HTTPS port which I accepted as default 5001. I wondered if that can be an issue, but it's not because PBX B has been set with the FDQN:5001 and can see PBX A.

I hope that makes sense, please feel free to check with me if you need further info. I'm at my wits end trying to get this one resolved, and would sincerely appreciate any help you can offer me.

 

[johnporteous]

Could this be approved for pasting please? Thank.

 

[AWS2P]

Are your bridge settings with FQDN on all pbxs or Pbx IP, if IP then change to FQDN

 

[Alphabetic]

Confirm firewall passes on PBX A.

Check that PBX C's IP is not blacklisted in PBX A

Check that PBX C has "Receive information" set correctly under "Presence" and that A is publishing.

 

[johnporteous]

Are your bridge settings with FQDN on all pbxs or Pbx IP, if IP then change to FQDN

They are all on FQDN, as previously.

 

[johnporteous]

Confirm firewall passes on PBX A.

Check that PBX C's IP is not blacklisted in PBX A

Check that PBX C has "Receive information" set correctly under "Presence" and that A is publishing.

Firewall passes on all 3.
Not blacklisted - whitelisted all IPs on each PBX.
All 3 PBXs have receive info selected and all extensions added. A is publishing, as B can see it and all the extension.

 

[Alphabetic]

im not sure that you can have 1 master with multiple slaves.

Can you try making 2nd master on A and connect up C using a different virtual extension?

 

[johnporteous]

im not sure that you can have 1 master with multiple slaves.

Can you try making 2nd master on A and connect up C using a different virtual extension?

I did swap them around. I previously had A as Master to both B and C. The only gotcha is you need to add a prefix on one of the two slaves because the outbound rule for 3 digit extensions doesn't allow to call both on 3 digits.
I'm pretty sure you can have 1 master with multiple slaves as I can call B and C from A, they can both call A. As as I mentioned, it was working up until Friday when I migrated.

 

[Alphabetic]

Then it could be a DNS issue, has IP's changed? Check your DNS servers.

 

[Alphabetic]

https://www.3cx.com/community/threads/bridging-set-up.81890/

Looks like I asked this question 2 years back. Not sure if it's changed.

 

[johnporteous]

We don't use DNS servers within our org; DNS for PBX is done by public DNS servers with the FQDN as always.
I don't see it as being DNS, because if you recall PBX B can see PBX A and vice versa; it's just C can't see A. If it was DNS, neither would be able to see A.

 

[johnporteous]

https://www.3cx.com/community/threads/bridging-set-up.81890/

Looks like I asked this question 2 years back. Not sure if it's changed.

Interesting. So essentially I need to configure A as Master to B; B as Master to C and C as Master to A is what you're saying? Like a round robin effect.

 

[johnporteous]

Could have sworn I tried that, but perhaps not. So obviously I will try again and report back, much obliged.

 

[Alphabetic]

Interesting. So essentially I need to configure A as Master to B; B as Master to C and C as Master to A is what you're saying? Like a round robin effect.

No.

PBX A (Master) B Slave
PBX A (Master) C Slave

and so on.

 

[johnporteous]

It is set that way.

In addition:
PBX B Master C Slave

All 3 need to talk internally. I can't see a reason that doesn't work? It's tunneling to a dedicated IP, just outbound rules need to be configured correctly if extension ranges are all the same. And they do. Purely the presence of A for C is not showing.

 

[Alphabetic]

Which PBX did you migrate? Does the WAN IP reflect the new one from the dashboard.

 

[NicholasP_3CX]

When you changed your port to 5001, did you add this to the presence? You will need to have FQDN:5001 in the presence page. Please note that the HTTPS port is not checked by the firewall checker so you will need to check that you have a new firewall rule to allow TCP:5001.

This IP might take a while to resolve with your DNS server(s).

 

[johnporteous]

Migrated PBX A, but done a full backup migration. Yes WAN IP is correct.

 

[johnporteous]

Yes I did, and it's working using that from PBX B to A as that Master/Slave works correctly.
All 3 are hosted in Azure; all 3 have the same firewall rules. I've actually disabled all 3's Windows FW/Defender as for some reason that kills the 3CX FW check.

 

[Alphabetic]

Can you access the mgmt console of PBX A from PBX C?