configure network card on RHEL

Edit configuration files stored in /etc/sysconfig/network-scripts/

You can configure network card by editing text files stored in /etc/sysconfig/network-scripts/ directory. 

First change directory to /etc/sysconfig/network-scripts/:

# cd /etc/sysconfig/network-scripts/

You need to edit / create files as follows:

• /etc/sysconfig/network-scripts/ifcfg-eth0 : First Ethernet card configuration file
• /etc/sysconfig/network-scripts/ifcfg-eth1 : Second Ethernet card configuration file

To edit/create first NIC file, type command:

# vi ifcfg-eth0

Append/modify as follows:

# Intel Corporation 82573E Gigabit Ethernet Controller (Copper)
DEVICE=eth0
BOOTPROTO=static
DHCPCLASS=
HWADDR=00:30:48:56:A6:2E
IPADDR=10.10.29.66
NETMASK=255.255.255.192
ONBOOT=yes


Save and close the file. Define default gateway (router IP) and hostname in /etc/sysconfig//network file:

# vi /etc/sysconfig/network

Append/modify configuration as follows:

NETWORKING=yes
HOSTNAME=www1.nixcraft.in
GATEWAY=10.10.29.65


Save and close the file. Restart networking:

# /etc/init.d/network restart

Make sure you have correct DNS server defined in /etc/resolv.conf file:

# vi /etc/resolv.conf

Setup DNS Server as follows:

nameserver 10.0.80.11
nameserver 10.0.80.12
nameserver 202.67.222.222

Save and close the file. Now you can ping the gateway/other hosts:

$ ping 10.0.80.12

Output:

PING 10.0.80.12 (10.0.80.12) 56(84) bytes of data.
64 bytes from 10.0.80.12: icmp_seq=1 ttl=251 time=0.972 ms
64 bytes from 10.0.80.12: icmp_seq=2 ttl=251 time=1.11 ms

You can also check for Internet connectivity with nslookup or host command:

$ nslookup cyberciti.biz

Output:

Server:         10.0.80.11
Address:        10.0.80.11#53

Non-authoritative answer:
Name:   cyberciti.biz
Address: 75.126.43.232

You can also use host command:

$ host nixcraft.in

Output:

nixcraft.in has address 75.126.43.232

nixcraft.in mail is handled by 10 mail.nixcraft.in.

source http://www.cyberciti.biz/faq/rhel-centos-fedoracore-linux-network-card-configuration/print/?k=true&r_POST_P_HELPER_ID=530