CentOS IPv6 Network Configuration

You need to update and configure following files for IPv6 configuration:

1. /etc/sysconfig/network : Turn on networking in this file.
2. /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,

• NETWORKING_IPV6=yes|no - Enable or disable global IPv6 initialization.
• IPV6INIT=yes - Enable or disable IPv6 configuration for all interfaces.
• IPV6ADDR=2607:f0d0:1002:0011:0000:0000:0000:0002 - Specify a primary static IPv6 address here.
• 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