[UkOpenBSDUsers] Using 6to4 tunnels with 6.8 and newer

Sevan Janiyan venture37 at geeklan.co.uk
Thu Feb 18 23:51:49 GMT 2021

It seems with the 6.8 release there was a change regarding IPv6,
changelog lists
"Set IPv6 source address selection to prefer the address with the
highest preferred lifetime in case of a tie."

With this, if you have a 6to4 gif tunnel and the same host has a routed
v6 address assigned to a "physical" interface (in my case it was a
virtio vio(4) interface), that address will not be reachable. If you
previously had a pltime value of 0 applied to the tunnel endpoint
address on your gif interface that will also break outbound v6
connectivity from the host it is configured on.

As a work around, you can move the routed address you had configured on
the "physical" interface previously to the gif interface as an alias.
Applying the pltime option to the endpoint address works fine then.

Needed this because online.net native v6 is terrible and needed the
pltime option working so that the origin of my outbound mail matched the
relevant DNS records.

2021: thought about switching back to v4only on a machine.


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