On 15 Mar 99, at 15:28, Herbert Graf wrote:

> ..., however what you should worry about is that if you do have IPX
> or netBeui (sp?) enabled, and sharing enabled, it is conceivable
> others on the same ISP could see your network drives, remote but it
> has been known to happen.

  This is (potentially dangerously) inaccurate.

  Windows network sharing is done using a higher-level protocol called
NetBIOS.  This is effectively integrated into NetBEUI, but it can also
be carried over top of TCP/IP (and I think also IPX, but that's much
less important).
  If you have file/printer sharing installed, in your Dial-up
Networking TCP/IP configuration there will be a checkbox for "NetBIOS
over TCP/IP".  [Recent versions of Win9x offer to disable sharing when
going online, at least for the first time....]

  If file/printer sharing and NetBIOS over TCP/IP are enabled, then
every time your PC connects to a host, it will send some special
messages asking if this is a Windows host offering shared
files/printers.  IT WILL ALSO ACCEPT SUCH REQUESTS FROM OTHER MACHINES
ON THE INTERNET.  [Some ISPs block such traffic between their networks
and the rest of the Internet, but not generally between customers on
the same subnet....]

  It's not too likely that someone would connect to your shared
resources by accident.  But if your machine is sending out share
queries like this -- I see 1000-2000 of them every day -- it's
practically inviting people to do the reverse....

  The crucial thing to note here -- the reason I thought it important
to follow up on Herbert's message -- is that enablind IPX and/or
NetBEUI is really irrelevant.  NetBEUI is restricted to a single
network/subnet ("it's not routable"), and while you can use RAS dial-up
into a LAN running IPX, it's not carried on the Internet.  To go on the
Internet, you have to use TCP/IP, and that will carry the NetBIOS
traffic and so expose you to this problem.


David G

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