Re: dhcpd(8) and unused or old MAC addresses

[Greg Troxel <gdt%lexort.com@localhost>]

Brett Lymn <blymn%internode.on.net@localhost> writes:

>> But dhcpd keeps track of previous leases long after their expiration; I
>> have had entires in the lease file from 6 months ago.  It will assign
>> addresses from the pool that have never been used for a lease, and then
>> I am pretty sure it will start reusing addresses probably in order of
>> least recently leased.  This is 100% compliant with the spec and means
>> that if a device gets an address and comes back next week, it will get
>> the same address.  I think this is what Rocky is seeing in the lease file.
>
> I have seen the opposite happen on a linux server where a vm I was
> constantly rebuilding would get a different IP despite the interface
> MAC being the same every time.

That is also spec-compliant behavior.

With dhcpd?

> As long as it doesn't double allocate it really shouldn't matter if
> dhpcd hands out the same address to something reappearing after the
> lease time has expired it.

Unless something or somebody cares.  It has no right to, per the
protocol, but it is often helpful to humans for it to be stable.  This
is why I suggested to Rocky to configure addresses.