Experiment No 1
Date: 30/12/24
Getting started with Basics of Network configurations files
and Networking Commands in Linux.
Aim
To familiarize with Network configuration files and Networking commands
in Linux
Theory
The following are some of the important network configuration files in Linux
operating systems
1. /etc/hosts
This file is used to resolve hostnames on small networks with no DNS
server. This text file contains a mapping of an IP address to the
corresponding host name in each line. This file also contains a line
specifying the IP address of the loopback device i.e, 127.0.0.1 is mapped
to localhost.
A typical hosts file is as shown
127.0.0.1 localhost
127.0.1.1 anil-300E4Z-300E5Z-300E7Z
2. /etc/resolv.conf
This configuration file contains the IP addresses of DNS servers and the
search domain.
A sample file is shown
# DO NOT EDIT THIS FILE BY HAND -- YOUR CHANGES WILL BE
OVERWRITTEN
nameserver 127.0.1.1
3. /etc/sysconfig/network
This configuration file specifies routing and host information for all
network interfaces. It contains directives that are global specific. For
example if NETWORKING=yes, then /etc/init.d/network activates
network devices.
4. /etc/nsswitch.conf
This file includes database search entries. The directive specifies which
database is to be searched first.
5.
The important Linux networking commands are
1. ifconfig
This command gives the configuration of all
interfaces in the system. It can be run with an
interface name to get the details of the
interface.
ifconfig wlan0
Link encap:Ethernet HWaddr b8:03:05:ad:6b:23
inet addr:192.168.43.15 Bcast:192.168.43.255 Mask:255.255.255.0
inet6 addr:
2405:204:d206:d3b1:ba03:5ff:fead:6b23/64
Scope:Global inet6 addr:
fe80::ba03:5ff:fead:6b23/64 Scope:Link
inet6 addr:
2405:204:d206:d3b1:21ee:5665:de59:bd4e/64
Scope:Global UP BROADCAST RUNNING
MULTICAST MTU:1500 Metric:1
RX packets:827087 errors:0
dropped:0 overruns:0 frame:0 TX
packets:433391 errors:0 dropped:0
overruns:0 carrier:0 collisions:0
txqueuelen:1000
RX bytes:1117797710 (1.1 GB) TX bytes:53252386 (53.2 MB)
This gives the IP address, subnet mask, and broadcast address of
the wireless LAN adapter. Also tells that it can support
multicasting.
If eth0 is given as the parameter, the command gives the details of the Ethernet
adapter.
2. netstat
This command gives network status information.
3. ping
This is the most commonly used command for checking connectivity.
4.ip
It is the latest version of ifconfig command and is used to show or
manipulate routing and network devices.
Syntax: ip a o r i p a d d r
5.traceroute
The traceroute command is a network trouble shooting utility which help us to
determine number of hops and packets travelling path required to reach a
destination.
Syntax: traceroute <destination>
6.tracepath
It traces the network path of the specified destination
Syntax: tracepath <destination>
7.ss
The SS command is a replacement for netstat command.
This command gives more information in comparison to the netstat
Syntax: SS
8.dig
It stands for Domain Information Groper.
This command is used for task related to DNS lookup to query the DNS
name server.
Syntax: dig <domain name>
9.nslookup
This command is also used to find DNS related Query
Syntax: nslookup <domain name>
10.route
The route command display and manipulate IP routing table for your system
Syntax: route
11.host
It displays the domain name for a given IP address and IP address for
a given hostname. It can also be used for DNS lookup.
12.arp
It is used to view and add content to the kernel’s ARP table.
Syntax: arp
13.iwconfig
It is used to configure the wireless network interface.
Syntax: iwconfig [options]
14.hostname
It is used to view and set the hostname of the system.
Syntax: hostname
15.curl or wget
To download a file from the internet
16.mtr
Combine Ping and Tracepath into a single command
17.ifplugstatus
Tells whether a cable is plugged in or not
