# IPv6 host with redundant gteway (VRRP)



## lungten (Dec 30, 2010)

We have IPv4/IPv6 network with redundant gateways. For IPv4 network, we use Cisco HSRP (RFC 2281) and for IPv6 network, VRRP (RFC 3768).

Now, since IPv6 doesn't support HSRP yet, we've used link local address (for example, FE80::30) as the redundant gateway address. This is configured as fail-over address between two gateways with proper IPv6 addresses. The only additional configuration required by the hosts here is to add the device/interface name through which to send traffic.

On Linux (CentOS/RHEL), we need to add the extra config line IPV6_DEFAULTDEV='eth0', for example. Since FreeBSD already uses interface names while configuring IP addresses, I thought the defaults should be fine. I didn't come across any other docs saying otherwise.

On Linux, it works fine but on FreeBSD it doesn't work well. It works for a while and then the IPv6 address just dies (cant ping from other IPv6 hosts). Sometimes, it doesn't work at all. But I can access services on the localhost via both lo0 and other interfaces.

Any idea on what additional configs I need to do or does this kind of setup work at all on FreeBSD?. I came across this thread which ends with the 'Link-local addresses are non-routable' post. That's true but I am trying to route via a link local address instead. Rest of the network configuration are taken care of by the gateway routers.

Since IPv6 on Linux is based on FreeBSD IPv6 networking code, I am sure the FreeBSD IPv6 is more advanced than that on Linux. Any hints would be of great help.


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