question about default resolvers

had a lot of issues today installing a plugin (host not found) and really could not ping anything.
looked at etc/resolv.con and see this:

Quote:

nameserver 74.91.20.18
nameserver 74.91.30.106


so I swapped it to the google ones and everything worked fine.
I THOUGHT the google ones were default anyways and am wondering what I may have done that would have changed that.

thanks.