how to set up ipv6 in linux server

On Red Hat / CentOS / Fedora RHEL:

Red Hat / CentOS / Fedora RHEL support IPv6 out of box. All you have to do is update two files and turn on networking.

/etc/sysconfig/network : Turn on networking in this file.
# 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=94.2 ms 64 bytes from 2001:4860:b002::68: icmp_seq=2 ttl=59 time=96.0 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=92.8 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. There are different ways to configure an IPv6 address on an interface. You can use use "ifconfig" or "ip". Automatic IPv6 Address Configuration In case, a Router Advertisement is received by a client, and IPv6 autoconfiguration is enabled (default on non-router), the client configures itself an IPv6 address according to the prefix contained in the advertisement Displaying existing IPv6 addresses First you should check, whether and which IPv6 addresses are already configured (perhaps auto-magically during stateless auto-configuration). Just note that addresses beginning with “fec0” are deprecated, but shown here for completness! Using "ip" Usage: # /sbin/ip -6 addr show dev <interface> Example for a static configured host: # /sbin/ip -6 addr show dev eth0 2: eth0: <BROADCAST,MULTICAST,UP&gt; mtu 1500 qdisc pfifo_ fast qlen 100 inet6 fe80::210:a4ff:fee3:9566/10 scope link inet6 2001:0db8:0:f101::1/64 scope global inet6 fec0:0:0:f101::1/64 scope site Example for a host which is auto-configured Here you see some auto-magically configured IPv6 addresses and their lifetime. # /sbin/ip -6 addr show dev eth0 3: eth0: <BROADCAST,MULTICAST,PROMISC,UP&gt; mtu 1500 qdisc pfifo_fast qlen ¬ 100 inet6 2002:d950:f5f8:f101:2e0:18ff:fe90:9205/64 scope global dynamic valid_lft 16sec preferred_lft 6sec inet6 3ffe:400:100:f101:2e0:18ff:fe90:9205/64 scope global dynamic valid_lft 2591997sec preferred_lft 604797sec inet6 fe80::2e0:18ff:fe90:9205/10 ¬ scope link 6.1.2. Using "ifconfig" Usage: # /sbin/ifconfig <interface> Example (output filtered with grep to display only IPv6 addresses). Here you see different IPv6 addresses with different scopes. # /sbin/ifconfig eth0 |grep "inet6 addr:" inet6 addr: fe80::210:a4ff:fee3:9566/10 Scope:Link inet6 addr: 2001:0db8:0:f101::1/64 Scope:Global inet6 addr: fec0:0:0:f101::1/64 Scope:Site