host-identifier with IPv6

Eustace, Glen G.Eustace at
Fri Feb 27 01:08:28 UTC 2009

> The koolaid that the IETF would have us drink is that instead of 
> recording the unique MAC address of a machine in the DHCP database, 
> we instead record the DUID that the OS generates when it starts up 
> the first time.  Then instead of having to update the MAC address 
> when replacing the Ethernet hardware, we get to update the DUID when > the OS is reinstalled.  And we get to record multiple DUIDs, one for > each OS on a multi-boot machine.  And we still have the problem of 
> PXE firmware using a different DUID that the OS.

This latter issue has driven me mad!!  I prefer not to hack code so haven't 'fixed' the issue by ignoring the dhcp-id for ipv4. But we have had to set lease lifetime down to 5 secs for PXE boots so that we don't run out of leases in several of our laboratory pools.

I didn't realise this was going to be a can of worms.  The best solution I can think of is to add in options that change the behaviour away from the 'standard'.  The default should be what the 'standard' says but if there are legitimate cases where the standard doesn't work for people, having the ability to change the behaviour by turning on/off an option would seem a pretty good compromise.
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