Networking

Networking

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classes of IP address
check first octect of IP address

A => 1 to 126 / 255.0.0.0
B => 128 to 191 / 255.255.0.0
C => 192 to 223 / 255.255.255.0

eg.

192.168.1.0 => network ID 192.168.1 And host ID = 0

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virbr0   Link encap:Ethernet HWaddr 52:54:00:C3:B1:30
inet addr:192.168.122.1 Bcast:192.168.122.255 Mask:255.255.255.0
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1> Steps to assign dedicated IP to server
i> #setup
Or
#system-config-network

ii> select “network configuration” => device configuration => eth0 ( or required interface/LAN card) => static IP ( type the IP) eg. 192.168.122.10 and other infomation ( clear the ‘*’ from DHCP ) => OK => save and quit.

iii> #service network restart

iv> #chkconfig network on

v> Disable the n/w manager
#vim /etc/sysconfig/network-scripts/ifcfg-eth0
NM_CONTROLLED = no ( By default Yes)
ONBOOT = yes

:wq

vi> disable LAN card
#ifdown eth0

vii> Enable LAN card
#ifup eth0

viii> cross check the assigned IP
#pifconfig

ix> finally check connectivity
#ping -c 3 192.168.122.10   —c(provide number of ping response count if want )
OR
#ping 192.168.122.10

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2> Assign IP temporarily
#ifconfig eth0 192.168.122.20

note : after reboot or n/w restart the temporary assign IP will lost

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3> Creating virtual LAN card
By using this, we can assign additional IP to same LAN card.

#ifconfig eth0:1 192.168.122.30
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4> Check hostname
#hostname

Change hostname temporarily
#hostname example.com

Change hostname permanently
#vim /etc/sysconfig/network
HOSTNAME=server.example.com

:wq

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5> Set domain name
#domainname example.com

Recheck domain name
#nisdomainname

Add entry to ‘hosts’ file
#vim /etc/hosts
127.0.0.1 example.com

:wq

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6> Add DNS member
#vim /etc/resolv.conf
search example.com

:wq

Now you can able to ping domain name
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Sample information in eth0 file

#cat /etc/sysconfig/network-scripts/ifcfg-eth0
DEVICE=eth0
ONBOOT=yes
IPADDR=192.168.122.10
NETMASK=255.255.255.0
GATEWAY=192.168.122.10
DNS1=192.168.122.10

:wq
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