Hosts and Domain Names

Domain Name System (DNS):
A DNS server translats host names (www.sun.com) to IP addresses.
A DNS server does not know all the IP addresses in the world;
rather, it is able to request other servers for the unknown addresses.

host, hostname: Look up host names using domain server.

 felix@lucas> hostname
 lucas

 felix@lucas> host localhost
 localhost.mantik.de has address 127.0.0.1

 felix@lucas> host lucas
 lucas.mantik.de has address 192.168.1.80

 felix@lucas> host server
 server.mantik.de is a nickname for linux.mantik.de
 linux.mantik.de has address 192.168.1.1

nslookup: Query Internet domain name servers.

felix@lucas> nslookup server
Server:  linux.mantik.de
Address:  192.168.1.1

Name:    linux.mantik.de
Address:  192.168.1.1
Aliases:  server.mantik.de

domainname: Show or set the system's NIS/YP domain name.

 felix@lucas> domainname
 mantik.de