I'm not a Maven ninja but I think Maven will try to reach the internet every time, it may not download a dependency but it will hit the network any way.
This is why I run the two previous commands when using Maven.
Any way, I'm investing a little in Gradle build tool these days, I think it is more practical than Ant, Gant and Maven
Yes, it'll go to the network--that's its job. But it shouldn't download the dependencies each time, unless both (a) the dependency versions aren't explicitly listed in the POM (in which case it will get latest) and (b) the dependencies are wildly updating themselves (possible, but not probable). Or something's wrong with the local repository and it's getting cleaned out over and over (more probable than (b)).
IMO something's wrong with the OP's setup and/or POM and/or cmdline. Going offline is certainly a solution, but may not be the most desirable one--that's all I'm saying.