Question about migrating to IPv6 with multiple upstreams.

Valdis.Kletnieks at Valdis.Kletnieks at
Tue Jun 14 17:38:27 UTC 2011

On Tue, 14 Jun 2011 13:04:11 EDT, Ray Soucy said:

> A better solution; and the one I think that will be adopted in the
> long term as soon as vendors come into the fold, is to swap out
> RFC1918 with ULA addressing, and swap out PAT with NPT; then use
> policy routing to handle load balancing and failover the way most
> "dual WAN" multifunction firewalls do today.
> Example:
> Each provider provides a 48-bit prefix;
> Internally you use a ULA prefix; and setup prefix translation so that
> the prefix gets swapped appropriately for each uplink interface.  This
> provides the benefits of "NAT" used today; without the drawback of
> having to do funky port rewriting and restricting incoming traffic to
> mapped assignments or UPnP.

Why do people insist on creating solutions where each host has exactly one IPv6
address, instead of letting each host have *three* (in this case) - a ULA and
two provider-prefixed addresses?
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