IPv6 Firewall on CPEs - Default on or off

Andre Tomt andre at tomt.net
Mon Dec 3 02:29:32 CET 2012


On 03. des. 2012 00:25, Lorenzo Colitti wrote:
> On Thu, Nov 29, 2012 at 3:13 PM, Andre Tomt <andre at tomt.net
> <mailto:andre at tomt.net>> wrote:
>
>     I propose setting the managed address flag in the RA's issued to the
>     LAN, and provide a DHCPv6 on the CPE doling out completely random
>     addresses.
>
>
> What about privacy addresses? They're sufficiently random, or at least
> as random as DHCPv6 assigned addresses?

They're fine for outbound but hosts still assign their MAC-derived 
address and will accept inbound connections on it, leaving them "easily" 
discoverable and accessible to the bad guys.

Most newer devices do support DHCPv6 addressing* so I don't see too many 
downsides of giving the managed addresses the full, unfiltered 
experience, leaving the others only outbound + return traffic. Other 
than making CPE's support something like it of course.

It effectively also fixing ND exhaustion on sweeping scans and allows 
you to not keep connection state for your (in practice) most chatty 
devices are just bonus features. :-)

* Most devices I've seen not supporting DHCPv6 addressing have so many 
problems with IPv6 that they dont belong on a public IPv6 network anyway.

-- 
André Tomt
Bob-bob.

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