Network utilities are small software utilities

Utility software

Utility software is system software designed to help analyze, configure, optimize or maintain a computer. A single piece of utility software is usually called a utility or tool....

 designed to analyze and configure various aspects of computer network

Computer network

A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....

s. The majority of them originated on Unix

Unix

Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...

 systems, but several later ports to other operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s exist.

The most common tools (found on most operating systems) include:

• ping
  Ping
  Ping is a computer network administration utility used to test the reachability of a host on an Internet Protocol network and to measure the round-trip time for messages sent from the originating host to a destination computer...
  
  , ping a host to check connectivity (reports packet loss
  Packet loss
  Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination. Packet loss is distinguished as one of the three main error types encountered in digital communications; the other two being bit error and spurious packets caused due to noise.-...
  
   and latency
  Lag
  Lag is a common word meaning to fail to keep up or to fall behind. In real-time applications, the term is used when the application fails to respond in a timely fashion to inputs...
  
  , uses ICMP
  Internet Control Message Protocol
  The Internet Control Message Protocol is one of the core protocols of the Internet Protocol Suite. It is chiefly used by the operating systems of networked computers to send error messages indicating, for example, that a requested service is not available or that a host or router could not be...
  
  ).
• traceroute
  Traceroute
  traceroute is a computer network diagnostic tool for displaying the route and measuring transit delays of packets across an Internet Protocol network. Traceroute is available on most operating systems....
  
  shows the series of successive systems a packet goes through en route to its destination on a network. It works by sending packets with sequential TTLs
  Time to live
  Time to live is a mechanism that limits the lifespan of data in a computer or network. TTL may be implemented as a counter or timestamp attached to or embedded in the data. Once the prescribed event count or timespan has elapsed, data is discarded. In computer networking, TTL prevents a data...
  
   which generate ICMP TTL-exceeded messages from the hosts the packet passes through.
• nslookup
  Nslookup
  nslookup is a network administration command-line tool available for many computer operating systems for querying the Domain Name System to obtain domain name or IP address mapping or for any other specific DNS record.-Background:...
  
  , used to query a DNS
  Domain name system
  The Domain Name System is a hierarchical distributed naming system for computers, services, or any resource connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities...
  
   server for DNS data (deprecated on Unix systems in favour of the tool called “host
  Host (Unix)
  host is a simple utility for performing Domain Name System lookups. It was developed by the Internet Systems Consortium , and is released under the ISC license, a permissive free software license....
  
  ” and dig; the preferred tool on Microsoft Windows
  Microsoft Windows
  Microsoft Windows is a series of operating systems produced by Microsoft.Microsoft introduced an operating environment named Windows on November 20, 1985 as an add-on to MS-DOS in response to the growing interest in graphical user interfaces . Microsoft Windows came to dominate the world's personal...
  
   systems).

Other network utilities include:

• spray, which sprays numerous packets in the direction of a host and reports results

Some usages of network configuration tools also serve to display and diagnose networks, for example:

• iproute2
  Iproute2
  iproute2 is a collection of utilities for controllingTCP and UDP IP networking and traffic control in Linux, in both IPv4 and IPv6 networks. It is currently maintained by Stephen Hemminger...
  
  (on Linux)
• ifconfig
  Ifconfig
  ifconfig is a system administration utility in Unix-like operating systems to configure, control, and query TCP/IP network interface parameters from a command line interface or in system configuration scripts...
  
  (on Unix)
• ipconfig
  Ipconfig
  ipconfig in Microsoft Windows is a console application that displays all current TCP/IP network configuration values and can modify Dynamic Host Configuration Protocol DHCP and Domain Name System DNS settings....
  
  (on Windows)
• route can display an IP
  Internet Protocol
  The Internet Protocol is the principal communications protocol used for relaying datagrams across an internetwork using the Internet Protocol Suite...
  
   routing table
  Routing table
  In computer networking a routing table, or Routing Information Base , is a data table stored in a router or a networked computer that lists the routes to particular network destinations, and in some cases, metrics associated with those routes. The routing table contains information about the...