ARP
ARP
RARP
An originating host must determine if a packet should be sent directly to a host in the local network or be directed to the gateway.
ANDing is used by a router, to see if the host which has to be contacted, is on the local network of the router, or a remote network.
Local delivery
The localhost address is designed to verify that the software for networking has been installed and is operating correctly. It does not pass any packets to the network.
the address Class
DNS stands for Domain naming system. it basicly translate ip address to host names and host names to ip address. If you use it on a local network it allows you to use your own naming conventions for your local subnet . Which helps to work easily in huge network need to remember only host names in network.
http://wiki.answers.com/Q/Do_packets_that_are_sent_to_host_on_the_same_local_network_need_to_be_translated"
When a host on network A sends a message to a host on network B, the router looks at the destination IP address in the packet’s header to determine where to forward the message. This IP address is used to identify the specific network and host within that network. The router uses its routing table to decide the best path for the packet based on this destination IP address. The MAC address is not used for routing between different networks, as it only applies to the local network segment.
You can communicate only with hosts on your own physical network and with hosts on networks for which an explicit route exists, but not with hosts which are beyond the gateway and where no explicit route exists. Or, you can reach local machines but you can't reach Internet machines.
Because they need a device to communicate with a distant network through. These devices are called gateways, and are normally routers. The hosts on a segment need to have knowledge of the gateway device in order to communicate outside the segment. In most environments, the local network will have an internal addressing scheme, one that is not routable on the internet, so there needs to be a device that can translate the internal addresses (non routable on the internet) into external addresses (routable on the internet). Of course this device needs to be connected to both the internal network and the external network to be able to send traffic between them.