[TriLUG] CentOS 5 and IPv6

[Brian Weaver]

I'm currently working on building an IPv6 only network for some product testing. I've built a small network using a dual NIC box running Debian Squeeze (gateway). The gateway box has an IPv4 address on one NIC and an IPv6 address on the other NIC. For the time being I'm going to ignore IPv6 Link Local addresses automatically assigned to each NIC. On the gateway box I'm running radvd (Router Advertisement Daemon) and ISC's DHCP Server for IPv6 on the IPv6 interface only.

I've configure a CentOS 5.6 host (dual NIC) so that one NIC is on the IPv4 network which allows me to remotely log in. The other NIC is configured so that it should only bring up the interface with a dynamically assigned IPv6 address using DHCPv6. On CentOS I've installed the dhcpv6-client package and tried to configure the network appropriately. I've been unable to get the address assigned via DHCPv6 because of what I think is a bug in the networks scripts; however I accept that the error may be an incorrect understanding of IPv6.

Below are my configuration files for the interested. If anyone has any suggestions then please let me know. FYI, the IPv6 NIC on the CentOS is marked not to come up by default during startup. This allowed me to do packet captures on the IPv6 network when I issued an "ifup eth1". So the fact that it doesn't attempt to address the IPv6 interface at startup is by design.

-- Brian

root at nerve120:~# cat /etc/network/interfaces 
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
allow-hotplug eth0 eth1

iface eth0 inet static
        address         192.168.42.120
        netmask         255.255.255.0
        broadcast       192.168.42.255
        gateway         192.168.42.1

iface eth1 inet6 static
        address         FCA8:6355:3904:1FC1:0000:0030:4858:882E
        netmask         64


root at nerve120:~# cat /etc/radvd.conf 
interface eth1 {
        AdvSendAdvert on;
        AdvManagedFlag on;
        AdvOtherConfigFlag on;
        prefix ::/64 {
                AdvOnLink off;
                AdvAutonomous off;
        };
};

[root at localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth1 
DEVICE=eth1
BOOTPROTO=none
ONBOOT=no
DHCPV6C=y

[root at localhost ~]# cat /etc/sysconfig/network-scripts/ifcfg-eth0
BOOTPROTO=dhcp
ONBOOT=yes
DEVICE=eth0