Sunday, January 3, 2010

ARP




ARP request and ARP replay.suppose i'm pining from 72.163.192.214 to 72.163.192.12.
now here is the pics which represent the arp request and reply packet.


ARP is used to map a destination IP address to its MAC
address.An ARP request when added to a IP datagram has the
following fields to it [Note that a ARP request packet isadded to the IP datagram in the DATA Field]...
1) Hardware Type [Ethernet/Token Ring .. Details]
2) Protocol Type [IP/IPX ..details]
3) Operation field
[ARP Req,ARP reply,Proxy ARF Req,Proxy ARP Reply]
4) H/w Length
5) Protocol Length
6) Source IP
7) Source MAC addr
8) Destination IP9) Destination MAC addr
Here the main focus will be on the fields 6-9 ..
6) Source IP [needs no explanation]
7) Source MAC addr [needs no explanation]
8) Destination IP [needs no explanation]
9) Destination MAC addr [This will be 0000:0000:0000]
Here is the full view of arp request:

ARP REPLY: