Couple of questions

twistfinger

I have 3 questions after studying for the net+ exam that I still don't know. Maybe I don't need them for the exam, but I'm still curious.

1) How do you see the addresses in a router's addressing table?

2) How does a router know where other networks are? Is there also a table of addresses for networks or does it send off to a DNS server to deal with?

3) How does a router know which computer to send responses back to if requests are seen as coming from itself and a web server sends the request back to the router? Do the packets still have the MAC address which the router can use to resolve to a network address?

Thanks.

dynamik

1) This probably varies from router to router. If you want to see an example, type "route print" into a console window in xp/vista (maybe 2000), and that will show the local routing table.

2) There are specific protocols such as OSPF and RIP that routers use to build routing tables. I don't believe routers use DNS since they're already working with IPs, but there might be an exception to this.

3) Basically, the router keeps track of which local machine is communicating with which remote machine.

Listen to these security now podcasts (25-27 on that page) that deal with how the internet and lans work: http://twit.tv/sn1?p=13

Those will likely fill in any gaps of knowledge you have. They're a great resource.

twistfinger

Thanks very much. I'll check out the podcast after work. I was looking for something like that.

dynamik

NP. You're not going to need to know any of that in-depth (maybe just something like OSPF is a routing protocol). Still give those podcasts a listen though; they're very well done. Give them all a listen if security is something of an interest for you, but those 3 in particular will help you out for this.