e name servers defined and they will be queried in order (useful if one goes down).For example ;The /etc/resolv.conf file from my machine is listed below.domain cqu.edu.aunameserver 138.77.5.6nameserver 138.77.1.1 4.18 The “nslookup” CommandA) nslookupThe nslookup command is used to query a name server and is supplied as a debugging tool. It is generally used to determine if the name server is working correctly and for querying information from remote servers.Like lpc, nslookup can be used from either the command line or interactively. Giving nslookup a hostname will result in it asking the current domain name server for the IP address of that machine.nslookup also has an ls command that can be used to view the entire records of the current domain name server.SECTION 55.1 ROUTINGA) RoutingRouting is the act of deciding how each individual datagram finds its way through the multiple different paths to its destination.For most UNIX computers the routing decisions they must make are simple. If the datagram is for a host on the local network then the data is placed on the local network and delivered to the destination host.If the destination host is on a remote network then the datagram will be forwarded to the local gateway. The local gateway will then pass it on further.5.2 ROUTING TABLESA) Routing tablesRouting is concerned with finding the right network for a datagram. Once the right network has been found the datagram can be delivered to the host.Most hosts (and gateways) on the Internet maintain a routing table. The entries in the routing table contain the information to know where to send datagrams for a particular network.B) Constructing the routing tableThe routing table can be constructed in one of two ways ;constructed by the Systems Administrator, sometimes referred to as static routes,dynamically created by a number of different available routing protocols5.3 The “netstat” CommandA) netstatThe netstat co...
