Address collision on range extended LAN after re-numbering main LAN

Client had decided to change ADSL provider. They got sent a new ADSL modem and I had to install this. The modem didn’t need any configuring as it was ready-to-go out of the box but its default LAN that it allocated¬† DHCP was 192.168.1.0/24 rather than the old LAN of 192.168.0.0/24

The client site has a SITECOM AP on this LAN and in another part of the building, a Belkin WIFI universal range extender that extended the WIFI. I had power cycled the SITECOM AP as it got its internet facing IP address from the DHCP server in the ADSL modem, but I never rebooted the range extender as it is in another part of the building and shouldn’t need to be rebooted.

The laptop that connects via the range extender was working fine but every few minutes Windows complained about an address collision.¬† The laptop is the only device on this range extender. The fix was easy – power cycled the range extender.¬† So though it shouldn’t need this as it’s using the different address space of the SITECOM AP (which is doing NAT), it did actually need doing.