many attempts to Port 137 (NetBIOS-NameService)

[joerg.walter () members debis at (Joerg Walter)]

Hi folks,
I discovered a strange thing on a Firewall (IPCHAINS-based, RedHat 6.0, Kernel 2.2.12-20). There are lots of 
connect-attempts to this machine to Port 137 (NetBIOS-NameService). These attempts are blocked but nethertheless I'm 
wondering, since the source of these packets are addresses throughout Europe and they doesn't seem to be broadcasts 
(destination address is exactly that machine). 
We have some other Firewalls set up just the same on the same network and they don't get these packets...

Is this something to be worried about?