On 06/02/2021 22:57, Bob Eager wrote:
On Sat, 06 Feb 2021 22:51:51 +0000, Steve Walker wrote:

On 06/02/2021 22:00, Chris Green wrote:
Harry Bloomfield, Esq. wrote:
Chris Green has brought this to us :
Unless you re-use addresses that happens anyway with DHCP, I don't
think any system on my LAN has ever changed its IP and nearly all are
assigned by my DHCP server.

Switched off, items can time out from the DHCP server, unless you set
them up not to.

Yes, but when they reconnect they get the same IP back. E.g. I go away
for weeks at a time with my laptop but when I come back home it always
gets the same IP. This is how it's meant to work, the DHCP server
*does* remember MAC addresses and will give the same address to the
same device every time unless there's a very good reason for not doing
so.

But if you have a power cut or switch the electric off to do some DIY,
the server and a number of devices will all lose power and may not get
the same addresses - they may, but there is no certainty.

There is certainty if you configure the DHCP server to assign a
particular IP address to a particular MAC address. That is what is being
said above by Chris, and it's how I do it too. I have absolute certainty
of IP addresses for all devices except those used by visitors (and they
come out of a small pool).

It was me that originally said that. My reading of Chris's post was that
he was saying that they normally get re-assigned the same IP address
anyway, without setting specific IPs in the DHCP server. Then I was
saying that they may not if restarting the network and devices after a
power out.