On Friday 21 March 2003 09:06, Mike Beattie wrote: > On Fri, Mar 21, 2003 at 08:26:36AM +1200, Nick Rout wrote: > > bravo good explanation Jim > > Indeed, I was going to answer this, when I got to work... but Helmut and > Jim did a pretty good bang up job :) > > So, Gareth, in effect, a router can be anything that joins two networks and > controls the traffic between. If you used an 'ethernet bridge', you'd spill > all your LAN traffic onto your DSL line, as Helmut implied.
Um, would you? I thought the *purpose* of an ethernet bridge was to keep two networks seperate, and only pass data between them that needed to be. An ethernet bridge would, I'm fairly sure, *not* spill local traffic onto the other side of the connection. Jim: my machine my not know the MAC address of google, but it doesn't need to, that's for upstream routers to figure out (as I think you went on to say?). When the ethernet frame leaves my computer, it will be stamped with the MAC address of it's "local" router / gateway, no? (and the IP packet contained within will be addressed to google). The ethernet bridge just needs to know the MAC address of the router/gateway on one side (at the ISP, for argument sake), it gets an ethernet frame from the local side with that address, and it passes it on out the other interface. It doesn't need to operate above layer 2. Of course this kind of setup would suck if you wanted more than one local client - then you would need to do IP masquerading, and the device in question would need to speak IP (ie. operate at layer 3), I agree. And then it is a gateway/router. Cheers, Gareth ps. out of interest, could someone please explain the difference (if any) between NAT and IP masq? Are they the same thing? Thanks.
