using ULA for 'hidden' v6 devices?

George Bonser gbonser at
Thu Jan 26 11:10:12 UTC 2012

> The potential advantage of ULAs is that you have a stable internal
> addressing scheme within the homenet, while your ISP-assigned prefix
> may change over time.  You run ULAs alongside your PA prefix.  ULAs are
> not used for host-based NAT.  The implication is that all homenet
> devices carry a ULA, though whether some do not also have a global PA
> address is open for debate.

Yeah, there's some advantage to that.  Have a "" domain that is the native domain for the internal machines while the domain that is visible to the outside world has outside accessible addressing.

> There's a suggestion that ULAs could be used to assist security to some
> extent, allowing ULA to ULA communications as they are known to be
> within the homenet.

Not sure how that assists security unless you simply want to limit site-site communications to your ULA ranges only, then sure.  In practice, sites often back each other up and you can have external traffic for site A using site B for its internet access, but that's not a big deal, just need to keep your internal and external traffic separated which any good admin will do as a matter of course, anyway.

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