[Node]

OK, let me improve my wording, if you are so picky on that...

I don't know about windows rules, but according to IP v4 standard 169.254.x.x subnet is reserved for APIPAs (automatic private IP addresses). These are not routable, etc. And are supposed to be used by IP v4 implementations as fallback addresses.

So you get an address from this range (random, or implementation dependent) when in DHCP mode but no DHCP OFFER unicast response is received in response to DHCP DISCOVER broadcast packets. OR when DHCP OFFER unicast is received, but DHCP ACK is NOT received in response to DHCP ACQUIRE unicast packet.

ICOM defaults to this address in DHCP mode by default. HOWEVER on newer firmwares if ICOM is set to DHCP AND it does not get DHCP OFFER within some timeframe since Ethernet link is established (I don't remember exact time amounts) it begins activating it's own DHCP server. After it starts, ICOM get's an address assigned by it's internal DHCP server. And it's this 192.168.4.1.

IP address of computer ALSO CHANGES after this, because computer ALSO sends DHCP DISCOVER messages periodically, NOT just once or twice. And eventually it gets DHCP OFFER from ICOM's internal DHCP. Followed by DHCP ACQUIRE/DHCP ACK packets pair.

Now if ICOM gets DHCP OFFER in time after establishing ethernet link from external (to ICOM) DHCP server, then it does not enable it's internal DHCP server, and the external DHCP is responsible for automatic IP configurations in the network.

In my shop I have DHCP server for quick operations. If I need to go offsite to a broken car, I really appreciate this new ICOM's internal DHCP. And then I'm happy to wait for a minute or two for it to kick in.