NetBIOS over TCP/IP not working through cable modem

[Sean Aitken]

Hi All!

Hopefully someone here can shed some light on my situation. I have a
Win2K server at home that I am trying to access from work. The Win2K
box is connected to the internet via a cable modem with a public IP. I
can use a variety of services against the box (VNC, HTTP, FTP, ping,
CVS) with no problem. However, when I try to access an NBT share or
resource, I get no response.

Facts:
- I have NBT enabled on my RoadRunner connection
- RoadRUnner support says they aren't blocking anything
- No traffic is being blocked from my work net (however, I am NAT'ing
out -- but I've accessed NetBIOS resources before from here)
- I can access my shares locally from the Win2K box by using
\\xxx.xxx.xx.xxx\.. THe IP I try this with is the RoadRunner assigned one
- I can telnet locally to port 135 and connect
- I can't telnet to 135 from work or a server I have with a hosting company

So, I'm stumped. I don't have any policies in place or firewall
software running. I have also tried cpaturing packets, of which I see
nothing. I'm starting to wonder if it is really Roadrunner thats
blocking the traffic, but the inept tech guy just didn't know.

Any tips / pointers or advice on solving this problem is greatly
appreaciated!

Thank you all!
-Sean

 

[Scott Harding - MS MVP]

Most likely it is your ISP. There really is no reason that this really
should work and most ISP do block netbios ports and some other ports like
SMTP which can help to stop worms, virus's etc. You shouldn't be doing it
like this anyways on an untrusted network. You should be using some type of
VPN connection or why don't you just use Terminal Services?

 

[Sean Aitken]

Hehe...
I've actually got some ehtereal output showing a block from TCP ports
135 through 139. Terminal services is a bit overkill, as I'm merely
trying to move files around. I've got my machine patched up pretty
tightly, and I enable the server service only when I need to do this. I
do have VPN access, but this particular issue is more political. I'm
really trying to ensure that when I DO need to NetBIOS to my machine
through my ISP that it's not going to be an issue.

Perhaps I'll dabble with Terminal Services...

Thanks for the info!
-Sean