Some background: I've been having intermittent network issues on my Win 7 laptop -- I have an apparently-good wireless connection, pinging the router works fine, etc, but sometimes web pages fail to load. Stranger still, certain sites would always work while others would always fail. Trying to ping "working" sites succeeded, but trying to ping "broken" sites failed.
Long story short, I beat my head against this for days and finally noticed that while my wireless adapter's config said it was using the correct default gateway (192.168.1.1),
ipconfig /all listed two default gateways -- the other was 192.168.1.89. I have no idea where it came from, and after trying everything else I could think of to get rid of it, I had to
route delete 0.0.0.0 then renew my DHCP. Hallelujah, everything is fixed, like magic.
Now, I lucked out and got some sysadmin mojo dredged up from the depths of my brain, this time -- but where the hell did that come from? No reason to think it's a virus (probably?), no recent installs of network-related software.... is this another case of Windows trying to be "helpful" that I haven't heard about? If not, what can have given me this bogus entry? Moreover, how can I prevent it in the future?