Well it was on automatic DHCP but since that's not working I'm experimenting with manual DNS entries copied from my router. Seems very strange that this just occurred out of nowhere. Every other device in the house is working fine so I doubt my internet provider made any changes.
I was able to operate my insteon devices thru the admin console but I think that uses the PLM and not the house network, is that correct? I am able to ping the IP address of the ISY from other PCs on the network so I think its only a problem getting out thru the router. I may try restoring my router to a previous configuration next just to see if that helps.