S300 Phones losing IP/Gateway/DNS after extension registration

I’ve been fighting with this for a week now and I am at a loss of what to do. I’m trying to deploy S500 and S300 phones the S500 are receiving an IP and Configs and just working. The S300 are receiving and IP, then losing it at receiving Configs. They are configured on a Chan_Sip on port 5160 due to 5060 problems with Spectrum internet.

Barracuda Firewall/Gateway
Cisco S300 managed switch
PBXact 100
7 S500 phones
38 S300 phones

During the initial bootup of the phone, it receives its IP address via DHCP and displays it on the phone then moves on to show “bridge mode” then the Mac address. It proceeds to get the updated firmware and its configurations and does a reboot. After the reboot, it will not show an IP address during the bootup but the DHCP server still shows it active. The Network Info page in the phone shows an IP of but the gateway and DNS are correct. If I reboot the phone again, the DHCP server does not show the phone online and everything in the Network Info page in the phone has been reset to zeros.

It only grabs an IP from a factory reset before it does a firmware update.

I decided to bypass the Cisco switch completely and run a dedicated LAN IP from the Barracuda. The S300 phones would receive the IP from the DHCP Server and attempt to register the extension. after attempting to register the extension, it would reboot and move everything in the IP config on the phone back and the phone would show offline on the DHCP server. I have reverted everything back to yesterday’s configuration in the Barracuda System since the switch did not resolve the issue.

S300 phones - I have learned I hate them.

  • Will not take an IP via DHCP after configurations and attempted registration of the extension
  • will not communicate to firewall/gateway with static IP configured on the phone
  • will not a reserved IP that is handed out by the firewall/gateway tied to the phones mac address, although the firewall/gateway will occasionally show it online, the phone itself will never show that it has an IP
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This really sounds like switch/network issue. Are you using vlans ?

He is using VLans

How should he configure the phones to work with VLans? the S500 work fine in the same environment.

I am using VLans and that was the problem. I am still using VLans, but have a work around.

A solution has been found. Not sure what is going on since the S500 phones work and the S300 phones do not.

With the help of another Sangoma Up and Running Specialist, we created a new template for the S300 phones to work off of. We copied the Sangoma_Default template and removed the VLan designation in the template, and moved all the S300 phones to the new template.

Once that was done and the phones were factory reset, they received the IP from the Barracuda AND held onto it after they registered their extensions and went through the firmware upgrade. No one fully understands why the S500 phones worked with Vlan designation but the S300 phones will not. For now, this is the solution that is working.

I still have much to learn about this system and thank you @chasemixon for support.

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The OS and VLAN side of the phones are 100% the same across all models. Are you sure you had the same firmware on the S300 as the S500 that was working as VLAN support was drastically changed months ago.

The S300 phones are booting with FW 4.30 and trying to upgrade to 4.31. I have changed the template to force 4.32.

I am unsure what the S500 phones are booting with initially, but they are sitting on 4.31 right now.


Disregard the previous post. I just now used a power adapter instead of POE and plugged in one S500 phone that has never been connected to the network and it is booting initially with FW 4.18. I then used the power adapter and left the S300 off the network and it is booting with FW 4.8.

I guess the phones were receiving the firmware of 4.31 after initially connecting to the rs.sangoma.net server.

The newer 4.18 vs 4.8 firmware could explain the reason why the S500 phones are holding onto the network configuration after registering the extension.

However, even after S300 received the 4.31 upgrade and a factory reset was done it would still gain the IP before it registered the extension and lose it after it attempted to register the extension.