Rhel/centos 6 (command line) Networking

Rhel/centos 6 does not configure network interfaces on default installation. Also, it's configured to use NetworkManager. To enable networking interface and disable NetworkManager please follow instructions below.

The/etc/sysconfig/network-scripts/ifcfg-eth0 content looks as follows on default installation.

Device= "Eth0″
HWADDR=SPECIFC MAC Address
Nm_controlled= "Yes"
Onboot= "No

For DHCP, configure the interface as follows.

Device= "Eth0″
HWADDR=SPECIFC MAC Address
Nm_controlled= "No"
onboot= "Yes"
Bootproto= "DHCP"

Restart the network after configuration.

/etc/init.d/network restart
Or
Service Network restart

For Static IP, configure it as follows

Device= "Eth0″
HWADDR=SPECIFC MAC Address
Nm_controlled= "No"
onboot= "Yes"
bootproto= "Static"
Ipaddr=ip address here.
Netmask=netmask here.

Change The/etc/sysconfig/network to the GATEWAY.

Networking=yes
Hostname=www.linuxbyanish.com
Gateway=gateway address here.

Restart the network after configuration.

/etc/init.d/network restart

To see current IP address information for eth0:-

# IP Addr Show eth0

To see routing information:

# IP Route Show

Ifconfig Command Example

Simply Type the ifconfig command as follows to display eth0 IP information:

# ifconfig Eth0

Eth0 Link encap:ethernet HWaddr b8:ac:6f:65:31:e5
inet addr:192.168.1.100 bcast:192.168.1.255 mask:255.255.255.0
Inet6 ADDR:FE80::BAAC:6FFF:FE65:31E5/64 Scope:link
Up broadcast RUNNING multicast mtu:1500 metric:1
RX packets:308560 errors:0 dropped:0 overruns:0 frame:0
TX packets:217836 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:431112624 (431.1 MB) TX bytes:20994801 (20.9 MB)
Interrupt:17
Type the following command to display a IP and its netmask:
# ifconfig Eth0 | grep ' inet addr: '
Sample outputs:
inet addr:192.168.1.100 bcast:192.168.1.255 mask:255.255.255.0

Rhel/centos 6 (command line) Networking