1) ifconfig = allows the operating system to setup network interfaces and allow the user to view information about the configured network interfaces

Examples

ifconfig

View the network settings on the Ethernet adapter currently used.

ifconfig eth0

View the network settings on the first Ethernet adapter installed in the computer.

ifconfig -a

Display into on all network interfaces on server, active or inactive.

ifconfig eth0 down

If eth0 exists would take it down causing it cannot send or receive any information.

ifconfig eth0 up

If eth0 exists and in the down state would return it back to the up state allowing to to send and receive information.

ifconfig eth0 192.168.1.102 netmask 255.255.255.0 broadcast 192.168.1.255

Assign eth0 with the above values for IP, netmask and broadcast address.

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2) ifup = bring a network interface up

ifup eth0 – bring up interface eth0

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3) ifdown = bring a network interfacedown

ifdown eth2 – bring down interface eth2

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4) ping = ping allows a user to ping another network IP address. This can help determine if the network is able to communicate with the network.

Example:

ping gmail.com – Would ping the gmailhost .com to see if it is alive.

ping gmail.com -c 1 – Would ping the hgmailost .com once and return to the command line

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5) traceroute = print the route packets take to network host

Examples:

$ traceroute google.co.in — Trace the route for Google Server.

$ traceroute -v 192.168.12.1 — Show more details.

$ traceroute -n server — Print the HOP Address in numeric form.

$ traceroute -I server
— Use ICMP ECHO instead of UDP datagrams.

$ tracerout
e -i eth1 server — Use eth1 for send the probe packets.

$ traceroute server 100
— Sent 100 Bytes packet instead of default 40 Bytes packet.

6) host = simple utility for performing DNS (Domain Name Service) lookups.  It is normally used to convert names to IP addresses and vice versa

Examples:

$ host google.com — Show the IP Address of Google.com.

$ host -v google.com — Show detailed output.

$ host -a google.com — Show more details.

$ host 127.0.0.1 — Do reverse lookup and Show the host name.

$ host -l mydomain.com — List all hosts available in MyDomain.

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7) dig = DNS lookup utility

Ecamples:

dig yahoo.com

dig 66.94.234.13

dig -x 192.168.52.

dig -t ANY yahoo.com