TCP/LP utilities

This chapter explains the functioning of different TCP/IP utilities including Ping, ARP, NETSTAT, NBTSTAT, IPCONFIG, WINIPCFG, Tracert, and ROUTE. Ping (packet Internet groper) is one of the easiest ways to test connectivity across the network and confirm that an IP address is reachable. The DOS ping utility (ping.exe) uses ICMP to forward an echo request packet to the destination address. The destination then responds with an ICMP echo response packet. The ARP utility (arp.exe) is used to display the arp cache which holds the IP to MAC address translation of hosts on the local subnet. This utility should not be confused with the ARP (address resolution protocol) that actually determines the IP to MAC address translation. The ARP utility can also be used to manually add entries to the cache, using the -s option. The NBTSTAT provides protocol statistics and current TCP/IP connections using NBT (NetBIOS over TCP/IP). This is relevant with Windows 95/98 etc, which uses NetBIOS for the upper layers of the OSI model. The IPCONFIG shows the entire TCP/IP configuration present in a host. It also has the additional versatility of interfacing with a DHCP server to renew a leased IP address.