LAN Saturated by Unwanted Transmission

["Thomas H. George" <tomgeorge@spininternet.com>]

I have three debian boxes on a wireless LAN.  Wnen my grandson's Windows 
XP is included on the LAN it saturates the system with transmissions.  I 
 installed tcpdump which shows repeated lines of transmissions to 
172.179.211.254.1781

I set up the LAN with no difficulty but I have zero experience in 
monitoring it.  How do I find out what this is?

Is there a good basic reference on monitoring which I should read?

Tom George