nbname outgoing to an external IP


I checked my logs and there I found that there commodo denied traffic from my PC via Port 137 to an external IP. The external IP change but in every case (I checked not all because there too much different IPs) there’s no registered Domain to theses IP’s, e.g.
Access denied, IP =, Port = nbname(137))
Protokoll: UDP Ausgehend (= Out)
Quelle (=Source): 192.168.x.xx:nbname(137)
Ziel: .
other IP’s are e.g:,,,
there are more different IP’s.

I don’t understand why my PC wants to contact via netbios external IP’s. Am I infected ???
I have scanned the PC with AVG and with Antivir and both found nothing.
My System ist XP Pro. I have DSL, a local network and a router. I use my wireless nic for both.

I’m more than a bit worried.


Edit: it’s XP Pro SP 2; netbios over tcp is active because it’s needed for the local network. I did’nt define a trusted network because of the wireless nic. I defined rules to allow the traffic to the static IP’s of the local network according to a tutorial in this forum -i don’t remember which one.
my recent firewall was the xp-firewall. ok I hope I haven’t forget something important.