Time to Remove Filters for Previously Unallocated IPv4 /8s

Document Type Expired Internet-Draft (individual)
Last updated 2011-02-18
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


It has been common for network administrators to filter IP traffic coming from unallocated IPv4 address space. Now that there are no longer any unallocated IPv4 /8s, this practise is more complicated, fragile and expensive. Network administrators are advised to remove filters based on the registration status of the address space. This document explains why any remaining filters for unallocated IPv4 /8s should now be removed on border routers and documents those IPv4 unicast prefixes that should not be routed across the public Internet.


Leo Vegoda (leo.vegoda@icann.org)

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)