On Thu, 6 Jan 2011, Jack Bates wrote:
Not stateful firewalls. He's referring to neighbor learning based on
incoming traffic to the router from the trusted side. ie, I received a
packet from the server, so I will add his MAC to my neighbor table.
There are many methods for learning MAC addresses, though. DHCP/MAC
security with static ARP and other viable options have properly killed
this problem in v4 by routers not looking for unknown neighbors.
When people start to talk about "trusted side" etc, I immediately think
firewalls and not plain routing. I don't trust anyone, neither my
customers, nor Internet.
I guess it might make sense to have the host register address usage (in
the SLAAC case) with the router, and the router having a mechanism to
broadcast/multicast to everybody that "I lost my state mac/ip table,
please re-register" so they can do it again.
It's how it works, but not how it should work. In the last years, v4 has
seen some nice implementations that specifically are designed
(especially for eyeball networks who have vast pools of space) to keep
routers from sending unsolicited arp requests and maintaining only a
valid pool of mappings.
In the DHCP case this is easy, yes.
I perfer to have only LL on the link towards the customer operated CPE,
thus I don't really need to keep lots of ND state per customer.
--
Mikael Abrahamsson email: swm...@swm.pp.se
