Netvanta 4305 DHCP problem?

[wullie]

I have a netvanta 4305, the DHCP range is set to 192.168.0.2 to141.

The ip address that is showing up on the computers is 192.168.30.xxx.  The computers are mostly win7 with a couple of macs and win10.

I have had some computers claim a duplicate ip address even though the router shows no conflict.

any insights would be great

[jayh]

It sounds like there is a rogue DHCP server on the LAN. Is there a switch behind the device? Does the 192.168.30.x network exist at the site?