access near pcs thro' routing table

From: cranium (cranium2003_at_yahoo.com)
Date: 05/28/04 

Date: 28 May 2004 08:13:34 -0700

hello,
      how can i know the adjecent computers or routers to my computer
at my linux workstation machine ? and how can i communicate to them if
i dont know there IP addresses? that meance how can i initiate a
communication to adjecent machines automatically? if it has given task
to periodically contact to its nearest one?
regards,
cranium