I am trying to connect 2 PCs directly with ethernet cable. One running Linux, acting as home server and it's headless, the other is a normal Windows laptop. Lets assume that both run some kind of IP auto-configuration; on Windows APIPA (Automatic Private IP Addressing), on Linux assume something like avahi-autoipd. Let's assume that that everything work correctly. APIPA, to my best knowledge, assigns random IP from 169.254.x.x range; I assume that avahi-autoipd does the same.
Question is: how can I get the IP address of the opposite node?
Lets assume that the opposite node, the Linux box, is headless so I cannot simply go there and read it there. Also it has no other network or other communication interface so I cannot, say, ssh there by the side channel and read it.