On Wed, Mar 14, 2001 at 01:39:52AM -0700, Jimmy Richards wrote: > On 14 Mar 2001 01:37:27 -0700, Jimmy Richards wrote: > > Hello There, > > > > I don't know too much about it, other than what it stands for Address > > Resolution Protocol. > > I know it's considered to be a 'low-level' protocol. > > The following is from my 'Desktop Computer Encylopedia 2nd Edition'. > > Anything in parentheses was > > added by me.... > > > > ARP > > Address Resolution Protocol > > > > A TCP/IP protocol used to obtain a node's physical address(maybe > > they mean MAC address by this?).
Yes, they're talking about the MAC id. It looks like this: narvi:/home/bem# tcpdump -v arp tcpdump: listening on eth0 09:03:44.740773 arp who-has thorin.cmc.net tell www.cmc.net 09:03:44.740996 arp reply thorin.cmc.net is-at 0:60:97:24:fd:a5 Pretty simple. > > A client station broadcats an ARP request onto the network(so you will > > see ARP requests for other machines) > > with the IP address of the target node it wishes to communicate with, > > and the node with that address responds > > by sending back it's physical address so that packets can be > > transmitted. ARP returns the layer 2 address for > > a layer 3 address. > > Since an ARP gets the message to the target machine, one might > > wonder why bother with IP addresses in > > the first place. The reason is that ARP requests are broadcast onto the > > network, requiring every station in the > > subnet to process the request. See RARP. And IP is routable, not to mention works on media other than ethernet.... -- CueCat decoder .signature by Larry Wall: #!/usr/bin/perl -n printf "Serial: %s Type: %s Code: %s\n", map { tr/a-zA-Z0-9+-/ -_/; $_ = unpack 'u', chr(32 + length()*3/4) . $_; s/\0+$//; $_ ^= "C" x length; } /\.([^.]+)/g;