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No Internet after UC320 Upgrade

Level 1
Level 1


I just updated the UC320. I didn't change anything else at the time, and we lost our internet connection.

I have confirmed:

- Modem IS working fine.

-With UC320 ethernet disconnected from switch, internet works fine.

- UC320 is still in route VOICE ONLY mode.

- I have restarted everything in my network including the modem, switch and UC320.

There seems to be some type of conflict with this new upgrade. Everything has been working fine for months prior. We really need help quick, as our phone system is down to support the office internet.

My setup.

UC320 in Voice ONLY mode.

SG-300 managed switch


5 Replies 5

Level 1
Level 1

Also, to be clear, we lost internet connection on our entire network. Not just the UC320.

When the UC320 is unplugged from the network, everything is fine. Plug the UC320 in and we loose our internet connection on every work station.

Heres an update. I got the internet working once again within the network.

I had to unplug the WAN on the UC320 to get it working, but this leaves me without internet on the UC.

My setup.

MODEM / ROUTER with 2 LAN outputs. One to the network switch SG300 and one to the UC320 WAN (now unplugged).

NETWORK SWITCH with a LAN output to the UC320 LAN to get data to other phones connected to the switch.

I assume it was creating a loop in this setup. The odd part is it had been working great for months. How am I to get internet back to my UC unit?

Hi Ryan,

A topology diagram would help in this case.  One thing to check is that you don't have any loops.  One common problem we have seen is people plug both the WAN port and the LAN port of the UC320W into the same subnet/switch.


Hi Chris,

This is how it was setup and working prior to the upgrade. Now the LAN to WAN cable from the router to uc320 has been disconnected leaving me without internet on the UC but keeping the network operational.

How would I get internet back on the UC without connecting the WAN?

Hi Ryan,

Can you configure your Modem Router with a DMZ port that is on a different subnet from the Modem Router LAN subnet?  OR can you configure a new VLAN in the Modem Router and associate the new VLAN with one port where you would plug in the UC320W WAN port?

Depending on your data network requirements you might be able to put the UC320W inline  like this:

Internet -- modem Router -- (WAN) UC320W(LAN) -- Switch -- PCs/Phones