Solved Phones - new phones showing up from different subnet

[jakthree]

3CX v15.5.15502.6
Phones
I have noticed that NEW Phone For Windows (bold letters) are showing up in the Phones tab. Some of the IP addresses are from a different subnet than the 3CX server. The 3CX server is 192.168.1.103. The NEW phone is 192.168.101.250. I understand that a new phone will broadcast a message and the 3CX server will see the message. I thought a message broadcast on 192.16.10.x subnet would not be seen by a server on the 192.168.1.x network.
What am I missing?

Thank you

 

[Mark Phillips]

What is the network address? i.e. how many bits in the subnet mask?

 

[jakthree]

local network address of the 3CX server is 192.168.1.103/24. (255.255.255.0)
running ip addr from terminal shows


IP of the phone that has shown is 192.168.101.250/22 (255.255.252.0)

 

[jakthree]

more about my network layout
there are two sites connected via VPN tunnel. Site-1 (primary) IP range is 192.168.100.x/22. Site-2 (secondary) is 192.168.1.x/24. There is a 3CX on premise server at site-1 and site-2. There is a 3CX bridge setup between site-1 and site-2 for purpose of intercom between sites. Each site has the own local PSTN gateways.

That being said, I didn't think broadcast traffic was suppose to cross subnets regardless of how the VPN is setup. So how does a new IP phone (or 3CX Phone For Windows) plugged into site-1 show up as new at site-2? (Site-2 phones don't show up as new at site-1)

 

[Mark Phillips]

Okay,
Firstly it's a multicast message not a broadcast message, although that doesn't really matter here as the rule is that a router shall not route multicast outside of the subnet.

Your /22 network is unusual because typical design would have a class C network 192.168 as /24 or smaller. That's not to say you can't do it, but I don't know whether your /22 network is causing some confusion in the routing table...quite possibly.

I have site to site VPNs and phones in one subnet will not auto provision to the 3CX server in another subnet (as expected).

 

[YiannisH_3CX]

A router can forward multicast messages from one subnet to another but has to be able to do so and configured to do so. The 3CX PBX listens for multicast messages from phones so if a multicast message arrives it will pick it up. A wireshark capture should help you check if the messages traverse the VPN.

 

[jakthree]

Mark,
You are correct about multicast instead of broadcast. I failed to remember what type of packet was sent. I knew what I was wanting to say but it didn't come out right.
Site-1 has 200+ IP devices which includes desktop workstations, servers, phones and other equipment. I created 192.168.100.x/22 (192.168.100.0 - 192.168.103.255) so that devices could be assigned to separate 255 groups. Workstation 192.168.100.x, devices/other 192.18.101.x, phones 192.168.102.x servers 192.168.103.x. I do use DHCP with a lot of reservations but it seems to works for us.
Site-2 has far less than 255 devices so it is all on one network 192.168.1.x/24. I also have a site-3 and a future site-4.

YiannisH_3CX,
I am checking router configuration on site-1 and site-2.
I think I found out what happened. A welcome message was sent to a user from the 3CX PBX at site-2 (PBX IP 192.168.1.103). The user, sitting at their desk at site-2 on the 192.168.1.x, proceeded to install 3CX iOS client on their iPad. I witnessed/helped with the installation. The user travels often between sites and picked up their iPad from site-1. I did not know the iPad was picked up form site-1 where it was assigned static IP of 192.169.101.250. After the provisioning was complete is when I noticed the NEW phone with an out of network IP.
Now that the users iPad is working, is it safe to delete the NEW (bold) entry from the Phones list or will deleting the entry cause the 3CX app on users' iPad to not work?

Thank you,

 

[jakthree]

YiannisH_3CX,
Ignore all that I said about the users iPad. That was not the problem!
I found that it was my computer was causing the issue. My computer is special that I have two NICs installed. First NIC is DHCP reservation 192.168.1.9. Second NIC is static with two IP address, 192.168.10.10 and 192.168.101.250. I had added the .101.250 to connect to a device some time back and I had forgotten to remove it when done with testing. I presume that when I installed the windows client that the client multicast out of all my IP's and the PBX caught them all as NEW phones. After I deleted the .101.250 address from my NIC then the NEW entry vanished form 3CX. I have other workstations that have multiple static IPs with one or more NICs. The lesson is I am now better prepared to deploy to those workstations.
I am sorry for my confusion.

 

[YiannisH_3CX]

Glad to see the cause has been found and thank you for updating the thread with your solution.