using ULA for 'hidden' v6 devices?

Ray Soucy rps at
Wed Jan 25 16:30:41 UTC 2012

We've used RFC1918 space for years (without NAT) for non-routed device
management (switches, printers, IP phones, etc).

The same idea applies to ULA.  Just another tool in the box.

The idea behind the random bits was to avoid conflicts should organizations
making use of ULA merge.

Locally managed means locally manage, though.  The RFC is more of
a suggestion than a requirement at that point.

Since it's unenforceable, and the standards require it
to function regardless, I do suspect that many will opt for a "random"
value of zero to keep the notation short and sweet, despite the RFC, or
develop an internal addressing schema for ULA space that works for them

On Wed, Jan 25, 2012 at 10:51 AM, Justin M. Streiner <
streiner at> wrote:

> Is anyone using ULA (RFC 4193) address space for v6 infrastructure that
> does not need to be exposed to the outside world?  I understand the concept
> of having fc00::/8 being doled out by the RIRs never went anywhere, and
> using space out of fd00::/8 can be a bit of a crap-shoot because of the
> likelihood of many organizations that do so not following the algorithm for
> picking a /48 that is outlined in the RFC.
> There would appear to be reasonable arguments for and against using ULA.
> I'm just curious about what people are doing in practice.
> jms

Ray Soucy

Epic Communications Specialist

Phone: +1 (207) 561-3526

Networkmaine, a Unit of the University of Maine System

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