Anarchists are, in a very general sense, against any government. However, it's such a silly utopian ideology that there are lots of equally incoherent variants of it including ones calling for total fed.gov control of all aspects of life, because otherwise the evil corporations will enslave you or something.
Libertarians, boiled down, believe that the only function of .gov should be enforcement of contracts and dealing with people who violate the NAP.