I think it is certainly reasonable to automatically test for system dependences before running the test suite. In your case, you need to ensure that the network is up and that certain services are available and listening, etc. As a part of this setup, you will learn IP and ethernet addresses that could be used in the test suite.
Once the initial setup is done, however, it would be best to arrange your test suite so that tests do not rely on any other system dependent stuff other than what was gathered during setup. The point of testing is to validate known output against known input, so reporoducibility is key and the actual test suite should be as machine independent as possible. This sort of attitude also helps you to eliminate implicit machine dependencies in the code you are testing.
