From: Kerodo (loopback_at_localhost.com)
Date: Sat, 19 Feb 2005 18:19:27 -0800
Can someone explain a few things about Netbios for me? I'm running a Win2k
machine here, no router, connected to the internet via a cable modem. The
usual software firewalls. I was playing around today and am confused about
a few things now.
I unloaded the software firewall (disabled it) and went to scan.sygate.com
and did some scans. First, I did a TCP scan, and it showed that my ISP is
blocking ports 135, 137-139 and so on. When I do a UDP scan, it says that
my ports 137-139 are OPEN.
Question: Why would my ISP block TCP Netbios, but not UDP Netbios? Isn't
Netbios UDP anyway?
Another question: If I ran without any firewall under the above
conditions, would people then be able to see what's on my hard drive via
UDP Netbios? Or is a TCP connection needed for this? Am I in danger with
UDP Netbios ports open but TCP Netbios ports blocked?
I also went into Windows network places config and disabled Netbios
completely and unchecked the other networking boxes. Just left TCP/IP
intact. So Netbios should be disabled. However, when I do a UDP scan at
Sygate, it still shows my 137-139 ports OPEN. What and why is this???
I'd appreciate any answers/comments to these questions. They probably show
my ignorance, but I'm curious. Don't have much experience with Netbios or
networks... Thanks to any and all...