Re:Rapid DHCP: Or, how do Macs get on the network so fast?
by saurik on Tuesday July 12, 2011 @08:34PM
(#2757260)
I'm confused... are you therefore suggesting that this is how people like Linksys should handle this problem? I fully realize that the spec was written in another time, but I don't think tzs did: he is actually citing the spec as a reason why these leases should stay around. When you go to a coffee shop, the router does not and probably should not play a chime when it has run out of DHCP leases, causing the barista to go around the room finding laptops that have been setup incorrectly... the router should, and almost certainly does, just "figure something out", likely by reclaiming addresses.
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Re:Rapid DHCP: Or, how do Macs get on the network so fast?
by caf on Wednesday July 13, 2011 @01:27AM
(#2757875)
There are sensible options available other than violating the leases.
For example, for a highly-used access point, it would make sense to give out only very short leases - say, 10 minutes. That'd support a churn of 25 clients per minute if you're giving out addresses from a /24 (and there's no reason why you couldn't use a smaller netmask, down to /8). It'd also be sensible to ignore a single MAC address once it had more than a handful of outstanding leases.
It doesn't help with a malicious client - but then neither does breaking leases. The malicious client can cause enough address flapping to make the network completely unuseable. You really can't protect a wifi network against a malicious client trying to DoS it - there's a myriad ways to do that apart from DHCP.