A sample .rhosts file might look similar to this (but contain more lines):
sp2101.ccs.ornl.gov hps101.ccs.ornl.gov sp2102.ccs.ornl.gov hps102.ccs.ornl.gov
Some systems require you to place your user_name on each line after the node or switch name. You will not need the dot extensions if you wish to access nodes of only that machine. Ask your system help about the naming of the nodes on the system you wish to use.