Those are internet (WAN) IP addresses - I'm guessing you're at a school or corporation that uses switches and configurable high-end router equipment? Unfortunately I have no experience on that equipment - hope someone else here does.
Any chance you have added a wireless access point/router?
On consumer-level routers, local versus WAN IP addresses are hard-coded into the firmware that filters requests to be sent to a higher-level DNS server versus the local hosts list. In other words, in my home, for instance, if my computers and printer had routable (WAN) IP addresses, a request to print would be sent outside of my router and come back to my router only to find that that port wasn't open. I hope that makes sense.