Red Hat / CentOS IPv6 Network Configuration
Q. How do I configure static IPv6 networking under RHEL 5.x / Fedora / CentOS Linux?
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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 }
1 June 15, 2010
you have no ipv6 mask :(
2 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.
3 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
4 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
5 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?
6 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″
7 October 20, 2010
Is there any directive to make network service start at boot time.
8 October 20, 2010
Try
chkconfig network on
9 October 20, 2010
I think that works for me, thanks Mr Vivek.
10 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 …
11 February 27, 2011
ipv6.google.com doesn’t resolve today, so it’s a bad example. Try http://www.v6.facebook.com.
12 June 10, 2011
any idea how to configure IPv6 in bridge for RH based OS?
13 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.
14 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
15 November 2, 2011
George – how about cp /etc/sysconfig/network-scripts/ifcfg-lo /etc/sysconfig/network-scripts/ifcfg-eth0