[cumbria_lug] Windows Network Noise on the Net.

Ian Linwood ian_linwood_clug at dinwoodie.freeuk.com
Wed Dec 22 09:36:40 GMT 2004


Hello Steve,

Wednesday, December 22, 2004, 1:29:14 AM, you wrote:


S> Hmmmmm...  got me wondering there as well (yes I know what I said 
S> earlier that I'm not adding to the noise on the net)...  I know I'm not
S> broadcasting netbios crap to the outside world from my router logs - not
S> a peep of it in sight, yet I don't have any specific iptables for it
S> (though I did!!!).

S> I think I'm right in thinking that netbios crap is only broadcast on the
S> local subnet?

Nil point! You are thinking of Netbeui. Netios travels over tcpip, and
can be routed.

S> If so, then as my firewall/router is acting as gateway
S> between two subnets and the stuff is only forwarded if and when I 
S> specifically address a machine on the other side, then I'm not actively
S> sending it out anyway or need to actively block it (per-se).

S> Which I suppose means, that anyone using a router with a private IP
S> range (192.168.x.x, 10.x.x.x, etc) NAT'd to the outside world won't have
S> the annoying netbios traffic forwarded.

All wrong!

S> Using a dialup modem however would be a completely different matter, as
S> the machine is on the net directly, and the local subnet *is* the 
S> internet!!!

Still wrong!

S> Also, using a bridge to pass traffic would have a similar problem to a
S> dial-up modem, as both sides of the bridge would be on the same subnet,
S> so the netbios traffic would be forwarded.

Still wrong. A bridge will pass ALL traffic, unless a specific filter is employed!

S> I feel like I'm doing Networking 101 here...  have I got it about right
S> though is the interesting question?

What do you think!  :-(


-- 
Best regards,
 Ian




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