Download Networking in Linux

Networking in Linux
Networking in Linux
Networking in Linux
♦ Introduction
A computer network is defined as a number of systems that are connected
to each other and exchange information across the network connection.
The system network is configured by setting the IP address which is
assigned by the system administrator. The IP address provides base
services for transmitting data between networks in TCP/IP (Transmission
control protocol/Internet protocol).
♦ Topics
► Network Connectivity
► IP address
► Accessing Remote system
► Transferring files
► Internet configuration
Networking in Linux
Networking in Linux
♦ The Linux system can be connected to the network with the help of
network hardware.
♦ Network hardware can be LAN (Local area network) card, cables,
hub/switch or router. To configure the network for the system, TCP/IP
(Transmission Control Protocol/Internet Protocol) address is required
from the system administrator.
♦ The IP address can also be obtained from the DHCP (Dynamic host
configuration protocol) server configured by the system administrator.
♦ When the system is connected to the network, the resources can be
shared and data can be transferred among the systems.
♦ The LAN services (telnet, SSH - Secure Shell, FTP – File transfer
protocol) enables the file transfer and remote login to the system.
Networking in Linux
IP Address
♦ An IP address is a 32 bit binary number usually represented as 4
decimal values, each representing 8 bits, in the range 0 to 255 (known
as octets) separated by decimal points.
♦ Every system in network is assigned a unique identifying number called
IP address.
♦ It is used in order to identify and communicate with different systems
present in the network.
♦ The data is sent across the network and contains a source and
destination IP address.
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Example:
10.10.1.240
130.130.1.10
192.168.1.200
Networking in Linux
IP Address
♦ Configuring IP address
The system can be a part of network by configuring the IP address. The IP
address can be set by two options in CUI mode and GUI mode.
►
Static IP
►
Dynamic IP (DHCP)
Networking in Linux
IP Address
♦ Static IP: A static IP address is configured manually by physically
entering the IP address in configuration dialog box and it does not
change until altered manually. The static IP is assigned by the system
administrator.
♦ Dynamic IP: In a large computer network, the process of assigning IP
address is simplified using a DHCP server. A DHCP server is used to
automatically assign the IP address to the computers that are configured
as a DHCP client.
♦ The following commands are used to configure and verify the IP
address from the command line prompt.
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netconfig
service network restart
ifconfig
ping
Networking in Linux
IP Address
♦ Static IP address in CUI mode
♦ Configuration of the static IP address
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Syntax
Type the command # netconfig (Press Enter key) at the command prompt
in the terminal window.
Networking in Linux
IP Address
♦ network service
►
Syntax
# service network restart
Networking in Linux
IP Address
♦ # ifconfig
Networking in Linux
IP Address
♦ # ping <IP address>
Networking in Linux
IP Address
♦ Dynamic IP address in CUI mode
♦ Configuration of the dynamic IP address
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Syntax
# netconfig (Press Enter key)
Networking in Linux
IP Address
♦ Static IP address in GUI mode
♦ Network configuration in static IP
Networking in Linux
IP Address
♦ Dynamic IP address in GUI mode
♦ DHCP settings
Networking in Linux
IP Address
♦ Host Name
A hostname is the unique name assigned to each host on the network. The
hostname is used to identify a particular IP address. Hostnames are used by
various naming systems like telnet, ssh, FTP, GFTP, NIS and DNS.
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There are three ways to resolve host names to IP addresses on a Linux
system:
• /etc/hosts
• DNS (Domain name service)
• NIS (Network information service)
Contd…
Networking in Linux
IP Address
♦ etc/hosts is a configuration file maintained locally on each host to
resolve hostnames to IP addresses. On a small network, it is easy to
maintain the name resolution of hostnames to addresses. When adding
or removing hosts, or reassigning IP addresses, the user have to update
the /etc/hosts file.
♦ DNS (Domain name service) will resolve the host names into IP
addresses in a large network.
♦ NIS (Network information service) provides a central point of
administration for common configuration files like /etc/passwd,
/etc/hosts. It preserves the consistency of the configuration files across
all the systems on the network. It simplifies configuration file updates
considerably.
Networking in Linux
Accessing Remote System
♦ Systems in the network can be accessed remotely with help of network
connectivity and using IP addresses in two ways:
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Telnet
SSH
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Telnet
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• Telnet is a terminal program for TCP/IP networks such as the Internet.
• The telnet program runs on your computer and connects your system to the
other system present in the network.
• To start a telnet session, you must log in to other system by entering a valid
username and password of the other system.
Contd…
Networking in Linux
Accessing Remote System
♦ telnet session
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Syntax
# telnet <destination IP address>
Contd…
Networking in Linux
Accessing Remote System
♦ SSH
SSH is a program for logging into a remote machine and for executing
commands on a remote machine
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The root user can login through SSH and execute the system administrative
command.
ssh command
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Syntax
ssh <destination IP address>
Networking in Linux
Transferring files
♦ Files can be transferred among various systems in the network by using
FTP, GFTP and SCP (secure copy).
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FTP
• FTP (File transfer protocol) is a program that allows you to transfer the files
between computers present in the network. It can also transfer the files among
different operating systems.
• Example: Linux to Linux, Linux to Windows, Windows to Linux.
• Syntax
# lftp <destination IP address>
Networking in Linux
Transferring files
♦ GFTP
GFTP (Graphical file transfer protocol) is the tool used for uploading and
downloading the files in a graphical mode.
♦ GFTP (Graphical file transfer protocol) session
Contd…
Networking in Linux
Transferring files
♦ SCP (secure copy)
► The scp command is used to copy the files from other system present in
network.
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Syntax
# scp <filename> <destination IP> : <destination path>
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Example: scp file1 192.168.1.171:/root
Networking in Linux
Internet configuration
♦ In Linux, internet can be browsed both in GUI mode as well as CUI
mode. The internet can be configured after the network connectivity.
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Configuring internet in GUI mode
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Step 1: Web browser (Mozilla)
Networking in Linux
Internet configuration
♦ Step 2: Proxy configuration
Contd…
Networking in Linux
Internet configuration
♦ Step 3: Setting the proxy IP and the port number
Contd…
Networking in Linux
Internet configuration
♦ Step 4: Verifying the Internet connectivity
Contd…
Networking in Linux
Internet configuration
♦ Modem
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Modem (stands for modulator-demodulator) is a device that enables a
system to transmit data over telephone lines for internet connectivity.
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It converts digital computer signals into analog format for transmission of
data.
Networking in Linux
Internet configuration
♦ Connection to internet through modem
Networking in Linux
Lab Exercise
♦ How to configure the IP address in CUI mode? Assume that your
system administrator or lab in-charge has given you the IP Address as
192.168.1.60?
♦ Check your system to be a part of network and communicate with other
systems present in the work
♦ Configure your system with Dynamic IP Address using DHCP
♦ Name the command to copy the files among the system in the network
with out using ftp?
♦ Name the command to copy the files among the system in the network
with out using ftp?