Red Hat / CentOS IPv6 Network Configuration

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Red Hat / CentOS IPv6 Network Configuration

by VIVEK GITE on JANUARY 23, 2009 · 15 COMMENTS


Q. How do I
configure static IPv6 networking under RHEL 5.x / Fedora / CentOS Linux?
<!--[if !supportLineBreakNewLine]-->
<!--[endif]-->


A. Red Hat
/ CentOS / Fedora RHEL support IPv6 out of box. All you have to do is update
two files and turn on networking.
You need to update and
configure following files for IPv6 configuration:
<!--[if !supportLists]-->1.    
<!--[endif]-->/etc/sysconfig/network : Turn
on networking in this file.
<!--[if !supportLists]-->2.    
<!--[endif]-->/etc/sysconfig/network-scripts/ifcfg-eth0 : Set
default IPv6 router IP and server IP address in this file.
Open
/etc/sysconfig/network file, enter:
# vi /etc/sysconfig/network

Append following line:

NETWORKING_IPV6=yes


Open
/etc/sysconfig/network-scripts/ifcfg-eth0 (1st network config file)
# vi /etc/sysconfig/network-scripts/ifcfg-eth0

Append following config directives for IPv6:

IPV6INIT=yes
IPV6ADDR=<IPv6-IP-Address>
IPV6_DEFAULTGW=<IPv6-IP-Gateway-Address>


Here is my sample file
with mix of IPv4 and IPv6 assigned to eth0:

DEVICE=eth0
BOOTPROTO=static
ONBOOT=yes
HWADDR=00:30:48:33:bc:33
IPADDR=202.54.1.5
GATEWAY=202.54.1.3
NETMASK=255.255.255.248
IPV6INIT=yes
IPV6ADDR=2607:f0d0:1002:0011:0000:0000:0000:0002
IPV6_DEFAULTGW=2607:f0d0:1002:0011:0000:0000:0000:0001


Where,
<!--[if !supportLists]-->§  <!--[endif]-->NETWORKING_IPV6=yes|no - Enable
or disable global IPv6 initialization.
<!--[if !supportLists]-->§  <!--[endif]-->IPV6INIT=yes - Enable
or disable IPv6 configuration for all interfaces.
<!--[if !supportLists]-->§  <!--[endif]-->IPV6ADDR=2607:f0d0:1002:0011:0000:0000:0000:0002 -
Specify a primary static IPv6 address here.
<!--[if !supportLists]-->§  <!--[endif]-->IPV6_DEFAULTGW=2607:f0d0:1002:0011:0000:0000:0000:0001 - Add a
default route through specified gateway.
Save
and close the file. Restart networking:
# service network restart

Verify your configuration by pinging ipv6 enabled site such as ipv6.google.com:
$ ping6 ipv6.google.com

Sample output:

PING ipv6.google.com(2001:4860:b002::68) 56 data bytes
64 bytes from 2001:4860:b002::68: icmp_seq=1 ttl=59 time=93.2 ms
64 bytes from 2001:4860:b002::68: icmp_seq=2 ttl=59 time=95.0 ms
64 bytes from 2001:4860:b002::68: icmp_seq=3 ttl=59 time=94.2 ms
64 bytes from 2001:4860:b002::68: icmp_seq=4 ttl=59 time=95.2 ms
64 bytes from 2001:4860:b002::68: icmp_seq=5 ttl=59 time=94.8 ms
64 bytes from 2001:4860:b002::68: icmp_seq=6 ttl=59 time=95.1 ms
64 bytes from 2001:4860:b002::68: icmp_seq=7 ttl=59 time=93.3 ms
64 bytes from 2001:4860:b002::68: icmp_seq=8 ttl=59 time=93.8 ms
--- ipv6.google.com ping statistics ---
8 packets transmitted, 8 received, 0% packet loss, time 7010ms
rtt min/avg/max/mdev = 93.268/94.376/95.268/0.799 ms


Traces
path to a network host, enter:
$ traceroute6 ipv6.google.com

Print default IPv6 routing table, enter:
$ route -n -A inet6

Sample output:

Kernel IPv6 routing table
Destination                                 Next Hop                                Flags Metric Ref    Use Iface
::1/128                                     ::                                      U     0      42531       1 lo
::62.41.14.144/128                          ::                                      U     0      0        1 lo
::127.0.0.1/128                             ::                                      U     0      0        1 lo
::/96                                       ::                                      U     256    0        0 sit0
2001:470:1f04:55a::2/128                    ::                                      U     0      15201       1 lo
2001:470:1f04:55a::/64                      ::                                      U     256    0        0 sit1
fe80::4833:22f4/128                         ::                                      U     0      0        1 lo
fe80::212:3fff:fe75:fa0d/128                ::                                      U     0      0        1 lo
fe80::/64                                   ::                                      U     256    0        0 eth0
fe80::/64                                   ::                                      U     256    0        0 sit1
ff00::/8                                    ::                                      U     256    0        0 eth0
ff00::/8                                    ::                                      U     256    0        0 sit1
::/0                                        ::                                      U     1      0        0 sit1


Once
IPv6 configured properly, you need to setup IPv6
firewall using ip6tables command under
Linux.

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{ 15 comments…
read them below or add one }

1Sean June 15, 2010



you
have no ipv6 mask :(
REPLY



2Beau July 13, 2010



Thanks
so much for this article. It is exactly what I have been looking for. I will
recommend this article. Keep up the good work.
REPLY



3Pete July 15, 2010



Nice
reminders, but I’d like to make two suggestions:
1.
Since the gateways are not specific to an interface, I keep the default gateway
stuff (v4 and v6) in /etc/sysconfig/network.
2.
I also don’t like the v6 autoconf for servers, so I turn it off in
/etc/sysconfig/network: IPV6_AUTOCONF=no
Thanks
for the quick tips.
Pete
REPLY



4Steve September 27, 2010



So
how would one find out there IPV6 address to use as a static one and what the
default gw IPV6 address us to use?
I
know the IPV4 addresses > how do i find its IPV6?
Thanks
in advance
REPLY



5SH October 7, 2010



I
try to add another interface (ifcfg-eth0:1) with the same IPv6 lines as in
ifcfg-eth0, but the IPv6 does not appear when I use ifconfig. How can I assign
an IPv6 to another network interface?
REPLY



6Pete October 7, 2010



Use
IPV6ADDR_SECONDARIES in ifcfg-eth0. Generally, v6 devices expect to have
multiple addresses. If you do an ifconfig on eth0, you’ll probably see at least
two v6 addresses already (one a link-local scope and one a global scope).
IPV6ADDR_SECONDARIES=”[/]
…” (optional)

A list of secondary IPv6 addresses (e.g. useful for virtual hosting)

Example:

IPV6ADDR_SECONDARIES=”3ffe:ffff:0:1::10 3ffe:ffff:0:2::11/128″
REPLY



7S!FE October 20, 2010



Is
there any directive to make network service start at boot time.
REPLY



8Vivek Gite October 20, 2010



Try

 chkconfig network on


REPLY

9S!FE October 20, 2010



I
think that works for me, thanks Mr Vivek.
REPLY



10tomas November 16, 2010



Just a question. How can
I calculate usable hosts address? I have assigned IPv6 /48 network and need
single adress for each server, for example

3x IPv6 address for server-1

2x IPv6 address for server-2

etc …
REPLY



11Joel Snyder February 27, 2011



ipv6.google.com doesn’t
resolve today, so it’s a bad example. Try http://www.v6.facebook.com.
REPLY



12Monster June 10, 2011



any
idea how to configure IPv6 in bridge for RH based OS?
REPLY



13Iain Kay July 22, 2011



I
have a question. If one has setup a CentOS server, and it is now in production
sitting online in use 24/7 with IPv4, is it possible to add IPv6 to it without
having to restart the network service?
What I have tried:

$ modprobe ipv6

$ ifconfig eth0 && ifconfig xenbr0
By
this point there are no ipv6 addresses shown in ifconfig
$
ip addr add 2001:xx:xx:xx:1::2/64 dev xenbr0
By this point I still
have no ipv6 addresses in ifconfig, all I get is:

RTNETLINK answers: Operation not supported
If
I absolutely have to reboot the server then I will find a good point to do so
and do it but if it’s even remotely possible to do without then that would be
ideal. The server hosts Xen virtual machines using bridged networking
configuration and somehow I doubt that restarting the network service would
play nice with them and come back automatically at Virtual Machine level.
REPLY



14George October 17, 2011



Hi
I dont find /etc/sysconfig/network-scripts/ifcfg-eth0, I only have
/etc/sysconfig/network-scripts/ifcfg-lo…….what can I do ? Help me please
REPLY



15Calum November 2, 2011



George
– how about cp /etc/sysconfig/network-scripts/ifcfg-lo
/etc/sysconfig/network-scripts/ifcfg-eth0