Hi,
Thanks for the reply.
I had turned off the DHCP server in the GUI and DHCP was not show in the services tab.
I can state however that this issue is not with pfSense or Squid.
I have traced a mobile user who's laptop had the Alureon malware infection, this took over DHCP services on the network and happened to display the Gateway and DHCP server as being the pfSense boxes LAN IP address. He happened to be at their head office today.
Whilst the following is OT it might just help someone.
In case anyone else has a similar issue here's how I traced it.
1. Disconnected servers and pfSense box from switch.
2. Connected laptop to master switch and it was assigned an IP (it shouldn't be)
3. Removed the 3 cascaded switches from the master and tried my laptop on each switch.
4. Laptop received an IP on switch #2.
5. In turn, removed each connection from switch #2 and repaired the laptops network connection.
6. Repeat until no IP is received, plug in the last removed connection and re-test.
7. Trace that connection to the patch panel and find out who's connection that is.
8. Leave that user un-plugged and re-patch all the other cables.
9. Reinstate that perfectly working pfSense box and sleep peacefully :D
10. Can't sleep, have a users machine to clean !!! DoH!!!
Thanks again
Andy Hodges