how to shut off netbios-ns/port:137 (udp)

From: Alex Fitterling (Alex.Fitterling_at_gmx.net)
Date: 06/03/03 

Date: Tue, 03 Jun 2003 15:42:34 +0200

Dear Microsoft Users,

when scanning certain win2k-clients in my network with the opensource
security tool nessus, I get following security warning: 

---
Warning netbios-ns (137/udp) . The following 2 NetBIOS names have been
gathered : NAME = Computer 1) name that is registered for the
messenger service on a computer that is a WINS client.  BENUTZER1 =
Computer name that is registered for the messenger service on a
computer that is a WINS client.  . The remote host has the following
MAC address on its adapter : XXXXXXXXXXXXXXXXXXX 1)
If you do not want to allow everyone to find the NetBios name
of your computer, you should filter incoming traffic to this port.
Risk factor : Medium
CVE : CAN-1999-0621
Nessus ID : 10150
1) due to security reasons the values has been made irrecognizable.
----
I definitely want to deactivate the whole port, not allowing the
clients to share anything on net. Is there a way to reach this, or
could that (only microsoft knows) for any reason be dangerous?
So far I took a look in certain newsgroups. There were actually a
whole bunch of inquiries I myself wasn't able to deal with. So this is
my own posting.
Sincerely,
Alex

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