Network Troubleshooting

Today let’s dive into some network troubleshooting. We’ll start with determining your IP address. there are a few commands that one can use for gathering their network information.

#ip addr
#ip a
#ip address show 
#ip a s

All of these produce the same output.  here is another tool, the ifconfig command. It’s slowly being phased out  IP command.

#ifconfig

The ping command is often used to test Internet connectivity. Ping will send one or more ICMP packets to a host. Be aware that ping will continue sending packets until the user stops it. To halt the ICMP packets simply press ctrl+c or use the “-c” option. the “-c” stands for count, so the program will only send a specified amount of packets. One should be aware that sites like Google and Facebook use firewalls to disregard ICMP packets that users

ping commands:

#ping <ipaddress>
#ping <option> <ipaddress>

  • #ping -c5 127.0.0.1 

    • a total of 5 ICMP packets will be sent
  • #ping -s 10 <ipaddress>

    • -s will specify the number of bytes sent
  • #ping -i eth0 <ipaddress>

    • -i option will allow the user to specify an interface

For more information about ping, you can either use the –help option or visit the man page. 

Traceroute is a command that shows you what “path” the packets have taken.
traceroute can be blocked by a router. These are often referred to as a hop indicated by an asterisk.

#traceroute <ip address>
#traceroute <option> <ip address>

A few of the many options you can use with traceroute. As usual, for more information use –help after traceroute or visit the man page.

  • -4 or-6 specify either only IPv4 or IPv6 based addresses
  • -i specifies an interface
  • -m will allow the user to adjust the maximum amount of ttl or hops
  • -q will set the number of probe packets per hop
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