[riskable]

...and the network intrusion detection system throws up all sorts of alarm bells about IPs being spoofed and duplicate IPs in use.

I assume MacOS actually only re-uses IPs if it sees the lease hasn't already expired but it might be dumber than that.

[lloeki]

IIRC it does, and otherwise throws out (or used to) an ARP check (or something like that) to see if any one on the local link is using the IP. A properly behaved DHCP server would not hand the IP again to someone else if the lease hasn't expired.

[nielsole]

> properly behaved DHCP server

One of the common issues with this is that home routers don't usually persist leases across power cycles.

[Fnoord]

IIRC DHCP leases should be refreshed at their half-time. Or perhaps I am mistaken and this is how Windows works.