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

[rockyhotas%firemail.cc@localhost]

On 2023-08-23 02:23, Greg Troxel wrote:
> > the address will be reused.
>
> This isn't really true.

I can confirm this, at least in my experience.

> 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.

Yes, it perfectly makes sense. I've never reached the point where the 
new
addresses are "sold out", so no "old" IP has never been reused so far, 
but
I think dhcpd(8) would behave this way.

> 1 hr, 1 day, is not going to matter much.  If you don't use all the
> addresses, a returning device (with same mac addr) will get the same
> address, even after a year.

I agree. My /var/db/dhcpd.leases includes entries almost older than two
years.

Rocky