UDP Port 137 Question

["John Smithson" <why1234 () hotmail com>]

Gurus,

I have couple of servers that are constantly trying to go outbound on UDP 
Port 137 (Nbname).  The event is occurring 4-5 times per second.  All 
outbound traffic is being dropped by my firewall.  However, I am just trying 
to find out what is the reason -

I have AV on the server with latest definition - I have ran manual AV Scan - 
I have ran Welchia / Nimda / etc removal tool - I have ran Spyware removal 
tool - All of them comes up clean. The outbound address are for example: 
156.67.52.182 to 156.67.52.204 --- 9.108.180.138-154 -- 145.46.77.202-241 - 
There are more of these network ranges ( I have already done whois on all 
these IP range)

Oh yeah - the servers are Win2k with SP3 or Win2k with SP4 with latest HF.

Please help me to isolate what I am facing?  This should not be a normal 
Traffic Pattern, since only couple of my servers are producing this traffic

TIA

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