What I cant seem to figure out is well. Say im at home and I fire up wireshark and start monitoring on wlan0, what I see is it only monitoring what im doing on this computer,none of the others, can this be changed without rerouting the traffic in iptables? second, say im using nmap and want to do a scan of my network and I know that my internal ip is so I assume scan ? third, say im at my brothers and I get an internal ip of do I assume scan fourth say, im at my house and my brother is having some network issues and I need to trouble shoot from my LAN to his, would I then scan his routers ip address? I just can't seem to figure out how this works: in wifi I get a dynamic ip for lease that would have there network prefix,subnet number in it and I'd get a host number at the end.STOP! how could this possibly work, with a max of 6 digits in there(Networkprefix,subnet#) how could that work globally? it don't add up to me, even if just the routers are actually communicating with the wire. All that aside I think it's a fair question, please shine some light on this subject for me (eys I do know about IPv6) but just cant get a grasp on this current situation.

advice would be greatly appreciated