IPv4 Configuration and Network Settings IN redhat linux

IPv4 Configuration & Network Settings

Network Support:

1. Boot system into a multi-user mode

2. /etc/modprobe.conf - contains alias and reference to module(s) to be loaded in order to provide networking

3. Linux decides if the interface is DHCP or static by viewing the contents of:

•/etc/sysconfig/network - networking=yes|no, IPv6_Support, Default Gateway, etc.

•/etc/sysconfig/network-scripts/ifcfg-eth0 - contains ifup, ifdown, and ifcfg-* scripts

•/etc/init.d/network - main service

GUI :
•service network status - checks networking
•system-config-network-* - network interface configuration

Note: Either update your net configuration manually from the shell, or using the 'system-config-network*' tools to avoid losing settings

/etc/resolv.conf - DNS configuration file
/etc/hosts - static list of hosts

IPv4 Aliases:

1. ifconfig eth0:1 192.168.75.11

2. ifconfig eth0:2 10.168.76.11

Note: To ensure that aliases persist do the following:

1. cp /etc/sysconfig/network-scripts/ifcfg-eth0 ./ifcfg-eth0:1

2. Modify ifcfg-eth0:1 to reflect aliased IP

Note: Aliases do NOT work with DHCP interfaces

ifconfig eth0:2 del 10.168.76.11 - removes the virtual interface

IPv6 Config:

Features:

1. Auto-configured by default gateway (router)

2. fe80:: - link-local address (loopback/local subnet address)

3. 2002:: - 6to4 address, that can be configured based on IPv4 embedded address,
using HEX notation

4.ping6 -I eth0 fe80::

5.traceroute6 - used to trace routes on IPv6 networks