The presentation layer of the OSI model conceptually does have its distinct purposes such as file format/encoding, compression, encryption etc. It's just that in practice it'ss basically always handled by the same piece of software which also implements the application layer functionality.
What kind of information is leaked through Wi-Fi?
Yup. Applel controls media access on all Ethernet hardware in the world.
That's why practically the TCP/IP model is better as far as the top of the stack is concerned, as it bundles everything above transport together as "application layer", as that's how it almost always works in the real world.
you can change them in software usually. they aren't randomized though, you have the same one forever unless you override it
you send a message asking to connect to a certain access point. everyone can read the message from the air. it has your mac and the name of the access point you want to connect to. if you've previously connected to 10 different APs, you will send probes to all of them whever you go. in wpa_supplicant you can turn this shit off. i dont know what other info is in wifi, probably tons, and tons of PII
Shit, am I safe if I don't use Ethernet?
Nigger, that was a joke.
en.wikipedia.org
Nigger, so was I
Fuck off here, we don't spoonfeed retards, you're not getting any pajeet points for this.
All of it. Just don't use a router
Almost everything. Physical location of IP, system brand and specs (cancer JavaScript scripts), data being transmitted to and from server and client, etc. I'd encourage you to look more into ARP spoofing if you want to learn more about MAC addresses, ARP and high level MITM attacks.
The entire OSI model from layer 1 to 7 and all most of the protocols are susceptible to man-in-the-middle and spoofing attacks, etc. You have to remember that the OSI model was created and implmented decades ago when protocols that transmitted data in plaintext was the norm. The icing on the shit-sandwich is the modern day 'web development' languages like JS and PHP that can fingerprint you when you visit a site. Most of the protocols today have SSL/TLS bolted on, which works for the most part, but E2E would be more preferable for security and some anonymity if we lived in a perfect world, but we don't.