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UC 320 DHCP handing out bad DNS


I have a UC 320 that is currently assigning the wrong DNS address via DHCP.  This happens on both the voice and data networks.

This happens regardless of wether or not the UC320 is set to 'Routes Voice Only' or 'Routes voice and data and is DHCP server' or 'routes voice and data with external DHCP'

Currently I have the 'routes voice and data w/external DHCP server' ,  when I connect my laptop to the voice network and get an IP address the DNS server is, which does not exist.  The voice network IP is currently 192.168.1.X/24 with UC320 as .1  .... just to be sure there was not a rouge DHCP server I changed the Voice network IP scheme from 192.168.1.X/24 to 192.168.10.X/24 and verified that I was getting DHCP from the UC320... the mystery DNS server of seems to show up no matter what I do.

UC320 has latest PATCHES.

I can not find anyway to change this.  The DHCP settings in the UC320, atleast mine, does not have a DNS server field.

Is it possible to change the DNS server that the UC320 handsout via DHCP ?  Please help



4 eagle ranch UC320.JPG

4 eagle ranch UC320 status.JPG


If you set up the uc320 wan type to dhcp it hands out the DNS address it receives from your wan interface (dsl modem, cable modem, ect.) check the DNS address your uc320 received in the networks overview screen.

What type of wan connection do you have at this site?

Sent from Cisco Technical Support iPhone App

The UC320 is behind a DSL and the WAN type is PPPoe (DSL), so the ISP is supply the DNS which is and

When I take the DSL connection out of the UC320 and connect it to my laptop and do the PPPoE from my laptop I get the above DNS servers.  I do not see the that the UC320 is handing out via DHCP.

any ideas?

Hi Jake,

Without trying this in the lab and grasping at straws without seeing your configuration, if you go to your WAN page and change the drop down from PPPoE to static IP.  Do you see the DNS field is populated on the Static IP template?

It may be time to put a call into the Cisco Small Business Support center where they can take a look at your configs.