Host names can be resolved by either using the /etc/hosts file or by using DNS.
Name resolution
hosts
The text file used on a local machine for hostname-to-IP address resolution is called the "hosts" file. It typically resides in the directory /etc/ on Unix-based systems (like Linux and macOS) and in C:\Windows\System32\drivers\etc\ on Windows systems. This file allows users to manually map hostnames to IP addresses, bypassing DNS queries for local resolution.
The nslookup command is a user interface to the DNS service, and provides name resolution lookup (among other things). It can also be used to debug problems with DNS resolution and the DNS configuration itself, return zone information, etc.
Unix is the name of an Operating System (software) and Cisco is the name of a technology company.
Most operating systems have a methodology for determining the host name of a client. On the command line, the command is usually 'hostname', for both Windows and Unix/Linux. From the GUI Windows perspective, looking at the System or Computer properties will reveal the hostname.
host
The file that typically contains a table of hostnames on a Unix-like system is called /etc/hosts. This file maps hostnames to IP addresses, allowing local hostname resolution. It is commonly used for network configuration and can be edited by system administrators to define local name resolution rules.
It can't be exactly the same name as root; directories in Unix have to be unique, and therefore you can't duplicate the name.
Name Resolution OrderTwo types of resolution are specific and standard. Microsoft resolves names two ways depending on whether the name is a TCP/IP host name or NetBIOS name. NetBIOS name resolution order for NetBIOS H-node: NetBIOS name cache - StandardWINS (3 attempts) - StandardNetBIOS b-node broadcast - Standardlmhosts file - Specific.hosts file - Specific.DNS - Specific. Request sent at 5, 10, 20, 40, 5, 10, and 20 seconds.
The client resolver cache is the first place that the DNS client looks for host name resolution. Because it is a location in memory, the client resolver cache resolves IP addresses more quickly than the other host name resolution methods and does not create network traffic. The cache stores host names that have recently been resolved. It also contains mappings that are loaded from the Hosts file. These mappings include the record name, Time-to-Live (TTL) value, and IP address.
By typing its name into the shell