Basic network troubleshooting

Few basic tools we use to troubleshoot networking issues are as follows.

  1. IFCONFIG
  2. PING
  3. NSLOOKUP
  4. TRACEROUTE
  5. TELNET

IFCONFIG

  • This command is used for viewing and changing the network interfaces of the system.
  • Wired connection interfaces will be displayed as <eth#> and wireless connections will be displayed as <wlan#>
  • Loopback interface will be displayed as “lo”.
  • If you want to specifically view details of a particular interface you can hit, ifconfig <interfaceName>
  • You can enable/disable a specific interface using up/down command. ifconfig <interfaceName> up/down

PING

  • This is used to send a signal to another device in the network to see if it is active.
  • ping <ipaddress/domainName> ping www.google.com

TRACEROUTE

  • This lets you see the step by step route a packet takes to a destination.
  • traceroute <domainName/ipaddress>

NSLOOKUP

  • This lets you query the IP address for a particular domain.
  • NSLOOKUP www.google.com will give you the ip address of google.com

TELNET

  • This can be used to see if a particular port of a server is accessible.
  • telnet <domainName/ip> <portNumber>
  • telnet google.com 80 will check if the port 80 is accessible on google.com

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