Chap 10 IP Addressing Andres, Wen-Yuan Liao Department of Computer Science and Engineering De Lin Institute of Technology andres@dlit.edu.tw http://www.cse.dlit.edu.tw/~andres

Overview The details of IP address classes, network and node addresses, and subnet masking The concepts you need to understand before configuring an IP address

Subnetting The purpose of IP address The role of host network on a routed network The role of broadcast addresses on a routed network The assignment of router interface and network IP addresses

IP address 32-bit dotted-decimal format Router interfaces must be configured with an IP address

The role of host network A host address all 1s: IP broadcast all 0s: "this network" or "the wire itself" The routing table contains entries for network or wire addresses

Broadcast Addresses The messages are intended to be seen by every host on a network Directed broadcasts Be directed into a specific network/subnet All 1s in the host portion of the address Flooded broadcasts (255.255.255.255) Local broadcasts

Router Commands ip addresses command ip host command ip name-server command Enable and disable DNS on a router Show hosts command

ip addresses command Establish the logical network address of an interface term ip netmask-format: specify the format of network masks bit count dotted-decimal (default) Hexadecimal

ip host command Make a static name-to-address entry in the router's configuration file

ip name-server Defines which hosts can provide the name service Maximum of six IP addresses

Show hosts command Display a cached list of host names and addresses

Verifying Address Configuration Verification commands The telnet and ping commands The trace command

trace command trace is supported by IP, CLNS, VINES, and AppleTalk !H -- Not forwarded by the router, usually due to an access list P -- The protocol was unreachable N -- The network was unreachable U -- The port was unreachable * -- Time out

Summary 32-bit logical address: IP address Broadcast messages ip address / ip host / ip name-server / show hosts telnet, ping, and trace