IPv6 routing /48s

Pekka Savola pekkas at netcore.fi
Wed Nov 19 07:28:06 UTC 2008

On Tue, 18 Nov 2008, Jeroen Massar wrote:
> Check: http://www.space.net/~gert/RIPE/ipv6-filters.html for a list of
> suggested filter expressions that cover all of these correctly.

Unfortunately, the JunOS version of the strict filter is blocking 
/32's from APNIC region as well.  The offending lines are:

             route-filter 2001::/16 prefix-length-range /19-/32;
              route-filter 2001:0c00::/23 prefix-length-range /48-/48;

This is because Juniper uses longest prefix matching in route filters 
(maybe this is different in cisco, I don't know):


As a result, this will end up rejecting legitimate prefixes such as 
2001:c00::/32 because then only /48's are accepted from that range.

Unfortunately, I don't know which blocks APNIC has set aside from 
2001:0c00::/23 for /48 assignments; based on their web pages, they 
have policies for at least multihoming, IXs and critical 
infrastructure.  But I couldn't find info which block these are from.

Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

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