nanog mailing list archives
Re: The stupidity of trying to "fix" DHCPv6
From: Leo Bicknell <bicknell () ufp org>
Date: Fri, 10 Jun 2011 07:28:02 -0700
In a message written on Fri, Jun 10, 2011 at 04:08:06PM +0200, Iljitsch van Beijnum wrote:
Ok, so now we've identified the problem. How exactly does adding default gateway information to DHCPv6 solve this problem?
Please go back and re-read my original scenario and think about it. The difference here is that if a client gets a DHCP address it generally won't be broken until it tries to renew, and then often won't be broken at renewal because it sends a directed request back. In specific technical terms: DHCP relies on broadcast _ONCE_ at boot, and then uses static unicast config to verify that is still the correct config. RA's use broadcast every few seconds to broadcast new information that everyone is supposed to "trust" instantly. Turn up a Rogue DHCP server on one of your subnets. It won't affect anyone who's already up and running. It may grab newly booted machines, depending on a race condition, but it won't break anything that is already working. Turn up rogue RA's, and everyone instantly fails. The behavior of these protocols is different, which leads to different failure modes. My assertion is that in every failure mode you can come up with RA's lead to more clients being down faster and for longer periods of time. -- Leo Bicknell - bicknell () ufp org - CCIE 3440 PGP keys at http://www.ufp.org/~bicknell/
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Current thread:
- Re: The stupidity of trying to "fix" DHCPv6, (continued)
- Re: The stupidity of trying to "fix" DHCPv6 sthaug (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Leo Bicknell (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Leo Bicknell (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Iljitsch van Beijnum (Jun 10)
- Message not available
- Re: The stupidity of trying to "fix" DHCPv6 Tim Chown (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Iljitsch van Beijnum (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 10)
- Message not available
- Re: The stupidity of trying to "fix" DHCPv6 Tim Chown (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Leo Bicknell (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Leo Bicknell (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Owen DeLong (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Chris Adams (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Jason Bertoch (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 William Herrin (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Ray Soucy (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Matthew Palmer (Jun 10)
- Re: The stupidity of trying to "fix" DHCPv6 Iljitsch van Beijnum (Jun 10)