What exactly does netsh int ip reset reset?
This is the first hit in google for the command you're asking about.
When you run the reset command, it rewrites two registry keys that are used by TCP/IP. This has the same result as removing and reinstalling the protocol. The reset command rewrites the following two registry keys:
It is shorthand for:
netsh int ip reset resetlog.txt netsh i i r r
The last 'r' being the "log file" that you really don't care to read.
What does it do? It hits your TCP/IP stack with a sledge hammer. And forcefully rebuilds it via a rewrite of two Registry keys:
This has the same effect as removing and reinstalling TCP/IP.
Please do this command in an Administrative command prompt http://www.thewindowsclub.com/how-to-run-command-prompt-as-an-administrator
I can tell you from experience that it removes any static IP information for all the NICs on the machine. I tried it on a server that was acting up and had to re-enter all the IP/netmask/gateway information for 6 network interfaces.
Interestingly enough, it did remember which interfaces were configured as static and what "items" were checked off on the interface (e.g. IPv4, Client for Microsoft Networks, etc). It also kept the interface names which we had previously changed.