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wrong DHCP address from UC520


Recently, I had a call where the client had someone else setup the UC 520 and esw520 about a year ago. He requested the tech put the voice on  the 10 network and the data on the 192. I noticed the esw520 is grabbing 192 ip's from the dhcp and not ip's. also, we are setting up another building and have already connected fiber. the data side works fine but the sg200 switch we have for voice is pulling 192 ip's and not 10.1 ip's. What needs to be done to make sure the voice is striclty on the 10 network? Thanks.

3 Replies 3

Thomas Gruendler

You usually always want the "admin access" for switches using a data vlan and not the voice vlan.  If the switches were configured corectly, they will pass both vlans. 

yes, but why would the phones not be able to access the tftp server. Also, why does the sg200 switch grab a 192 address? I understand that the voice is on vlan 100 and the data is on vlan 1. vlan 100(voice) is on the 10 network and vlan 1 (data) is on the 192 network.

Hi Wayne,

The switch will operate in the management VLAN-1 which should be the data VLAN, via CDP if the SG-200 has direct access to the UC, it should auto provision the Voice VLAN assuming it has the latest firmware to support the CDP configuration.

If the phones are not registering or are obtaining an IP address from another DHCP source, then the VLAN configuration is messed up on the SG-200 and you need to resolve that.

Let us know if you need further clarification.



Cheers, David Trad. **When you rate a persons post, you are indicating a thank you or that it helped, but at the same time you are also helping to maintain the community spirit - You don't have to rate posts and you wont be looked down upon :) *
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