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NTP over WAN


My client's UC320 is tucked behind an RV220W router/firewall. My client does not have a file server, just a handful of XP/Win7 desktops. I need to get NTP service to the phone system because every time it restarts, the time resets to December 1999, 7PM, which turns on the AA schedule immediatelly. No calls get through until I scramble to get the correct time set on a SPA phone. The NTP .PMF file wants a time server on the local network, which they don't have. Since the UC320 doesn't know the gateway to the internet, it can't see any NTP server's out there. Is there some trick or way around this?


4 Replies 4

Cisco Employee
Cisco Employee


Can you add NTP service to one of the local pc's?

Here is a Microsoft article on how to add NTP service to Windows XP pc:



Is the WAN port of the UC320W connected to the RV220 for internet access?  If so, you probably don't need the NTP pmf to reach the public NTP server on the Internet.


The LAN port of the UC320W has an uplink to a Cisco switch. That switch has an uplink to the RV220 for internet access. Could I VLAN the WAN port of the UC320W to the RV220? I know I can't use the same subnet for both the LAN and WAN on the UC320..

(Thanks Randall - I will look into that article from microsoft on NTP for XP. But I would still like to learn a way to do it with just the Cisco equipment)


Hi Tracy,

Yes, you can add a new VLAN, say 5, on the RV220.  Make the port that the UC320W is plugged into on the RV untagged on the new VLAN.  Make sure your new subnet on VLAN 5 does not conflict with any of your existing subnets (data and voice).  See example below.  UC320W would be connected into Port 1 of the RV220.  (click to enlarge)

Now you won't need the NTP PMF.  Hope this helps.


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