[arin-ppml] ULA-C and reverse DNS

michael.dillon at bt.com michael.dillon at bt.com
Mon Mar 22 12:30:22 EDT 2010

> Are you suggesting that each sub part of an enterprise should 
> be able get its own /48?  Are you suggesting there should be 
> no limit to the number of /48s a enterprise can get?  It 
> sounds to me like that is what you are suggesting.

There is a natural limit on the number of ULA-C prefixes that
an enterprise can get. If they only want to route locally in
some lab or local infrastructure, then they can get a ULA-C 
block. Later, if what they have built becomes valuable to the
enterprise, they can route that ULA-C block enterprise wide
with confidence that it won't break anything. But, the new 
block will not function enterprise wide unless they can 
convice the IT admins to unblock that network in their firewall
ACLs. It is common for there to be multiple layers of firewalls
internal to an enterprise and the policies are roughly to block
all traffic that is not known and registered in their IT registry.

--Michael Dillon

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