Here is their documentation on interface creation:

 https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/3/html/Reference_Guide/s1-networkscripts-interfaces.html

Add this line if it does not exist to /etc/hosts

127.0.0.1 localhost localhost.localdomain 

run the following commands as root

# ifconfig lo 127.0.0.1 # route add 127.0.0.1 

Test the interface

 # ifconfig lo lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:3924 Metric:1 RX packets:60 errors:0 dropped:0 overruns:0 frame:0 TX packets:60 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 # ping localhost PING localhost (127.0.0.1): 56 data bytes 64 bytes from 127.0.0.1: icmp_seq=0 ttl=255 time=0.3 ms 64 bytes from 127.0.0.1: icmp_seq=1 ttl=255 time=0.2 ms 64 bytes from 127.0.0.1: icmp_seq=2 ttl=255 time=0.1 ms 64 bytes from 127.0.0.1: icmp_seq=3 ttl=255 time=0.1 ms 64 bytes from 127.0.0.1: icmp_seq=4 ttl=255 time=0.2 ms 64 bytes from 127.0.0.1: icmp_seq=5 ttl=255 time=0.1 ms --- localhost ping statistics --- 6 packets transmitted, 6 packets received, 0% packet loss round-trip min/avg/max = 0.1/0.1/0.3 ms 

Here is their documentation on interface creation, titled:  Red Hat Enterprise Linux 3: Reference Guide - Chapter 8. Network Interfaces.

1. Add this line if it does not exist to /etc/hosts

    127.0.0.1 localhost localhost.localdomain 

2. run the following commands as root

    # ifconfig lo 127.0.0.1 # route add 127.0.0.1 

3. Test the interface

    # ifconfig lo lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:3924 Metric:1 RX packets:60 errors:0 dropped:0 overruns:0 frame:0 TX packets:60 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 # ping localhost PING localhost (127.0.0.1): 56 data bytes 64 bytes from 127.0.0.1: icmp_seq=0 ttl=255 time=0.3 ms 64 bytes from 127.0.0.1: icmp_seq=1 ttl=255 time=0.2 ms 64 bytes from 127.0.0.1: icmp_seq=2 ttl=255 time=0.1 ms 64 bytes from 127.0.0.1: icmp_seq=3 ttl=255 time=0.1 ms 64 bytes from 127.0.0.1: icmp_seq=4 ttl=255 time=0.2 ms 64 bytes from 127.0.0.1: icmp_seq=5 ttl=255 time=0.1 ms --- localhost ping statistics --- 6 packets transmitted, 6 packets received, 0% packet loss round-trip min/avg/max = 0.1/0.1/0.3 ms 

Here is their documentation on interface creation:

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/3/html/Reference_Guide/s1-networkscripts-interfaces.html

Here is their documentation on interface creation:

https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/3/html/Reference_Guide/s1-networkscripts-interfaces.html

Add this line if it does not exist to /etc/hosts

127.0.0.1 localhost localhost.localdomain 

run the following commands as root

# ifconfig lo 127.0.0.1 # route add 127.0.0.1 

Test the interface

 # ifconfig lo lo Link encap:Local Loopback inet addr:127.0.0.1 Mask:255.0.0.0 UP LOOPBACK RUNNING MTU:3924 Metric:1 RX packets:60 errors:0 dropped:0 overruns:0 frame:0 TX packets:60 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 # ping localhost PING localhost (127.0.0.1): 56 data bytes 64 bytes from 127.0.0.1: icmp_seq=0 ttl=255 time=0.3 ms 64 bytes from 127.0.0.1: icmp_seq=1 ttl=255 time=0.2 ms 64 bytes from 127.0.0.1: icmp_seq=2 ttl=255 time=0.1 ms 64 bytes from 127.0.0.1: icmp_seq=3 ttl=255 time=0.1 ms 64 bytes from 127.0.0.1: icmp_seq=4 ttl=255 time=0.2 ms 64 bytes from 127.0.0.1: icmp_seq=5 ttl=255 time=0.1 ms --- localhost ping statistics --- 6 packets transmitted, 6 packets received, 0% packet loss round-trip min/avg/max = 0.1/0.1/0.3 ms