ServerBuddies Support Blog

Disable IPv6 in RHEL5

Unless your policy or network configuration requires it, disable IPv6.

To do so, prevent the kernel module from loading by adding the following line to
/etc/modprobe.conf

Next, add or change the following lines in /etc/sysconfig/network:

How do I disable IPv6?

Redhat recommends not disabling the ipv6 module, as that can cause issues with SELinux and other components, but adding the following to /etc/sysctl.conf will disable IPv6.

Disable ipv6 on RHEL 4 and 5

Edit /etc/sysconfig/network and change

Edit /etc/modprobe.conf and add these lines (if they’re not in it):

Stop the ipv6tables service by typing:

Disable the ipv6tables service by typing:

IPv6 will be disabled after the next reboot of the system.

IPv6 Addresses Types

IPv6 addresses are broadly classified into three categories:

1) Unicast addresses A Unicast address acts as an identifier for a single interface. An IPv6 packet sent to a Unicast address is delivered to the interface identified by that address.

2) Multicast addresses A Multicast address acts as an identifier for a group/set of interfaces that may belong to the different nodes. An IPv6 packet delivered to a Multicast address is delivered to the multiple interfaces.

3) Anycast addresses Anycast addresses act as identifiers for a set of interfaces that may belong to the different nodes. An IPv6 packet destined for an Anycast address is delivered to one of the interfaces identified by the address.

IPV6 Network Configuration in Linux

Add nameserver to resolv.config

vi /etc/resolv.conf

Add line for ipv6 nameserver

vi /etc/sysconfig/network

Add a line at the bottom

vi /etc/sysconfig/network-scripts/ifcfg-eth0

Add lines at the bottom

Restart network services: