By the way, are you sure there are 7 layers? I'm guessing you are referring to
this model, but it was my understanding that
this one was used for The Internet, which has only 4.
(at the risk of opening an even bigger can of worms...)
both models say the same thing, but in different ways, there are 4 layers in the IP model and 7 Layers in the OSI model.
they match up like this
OSI1 (physical) + 2 (Data link [hardware addresses]) = IP model link layer
OSI3 (Network [IP address]) = IP model IP layer
OSI 4 (Transport protocol [udp/tcp etc]) = IP model Protocol layer
OSI 5, 6, 7 (session, [i.e sockets] presentation [popping data out the socket] and Application [Presenting stuff to the user])= IP Protocol layer.
(both are weirdly disconnected from reality when you actually write a program, its your program that dictates the protocol TCP/UDP your program that requests the port number, your program manages the sockets and your program displays the data.
so, OSI model layers 4, 5, 6, and 7 are all managed by your application.
IP model layers 3 and 4 are all managed by your application!
(which makes it really unhelpful from call layer 4 or 7 the "application layer" when so much more is managed by your application.)
(so they are sometimes described as Media layers, and host layers... - which again makes no sense as the host (computer) has control of the top of the media stack as it is the host that sets the IP address.)
it does makes sense to use the IP model when talking about a firewalls or routing internet stuff as what you really have is:
layer 1, is the wire plugged in.
layer 2, are the addresses right
layer 3, what port and protocol is used.
layer 4 all the crap that any device (router/firewall) does not care about.
I don't think my ISP gives a sh* about them. I was thinking some other countries, especially Eastern ones, which usually don't give a f* about "freedom". Maybe US ISPs also log it to try to stop criminal activities and such, like terrorism maybe (like terrorists will be using Facebook and WhatsApp).
I would expect that they would not care, they should not care, the fact that they can be changed easily, (on I think any OS) would call into question the reliability of that evidence anyway... but like I said before, if the police already know what door to come to, what network they want to infiltrate to try to nail down your one computer, there is a strong chance that they know where/who you are already, and just want to catch you in the act.
the silk road guy, who I mentioned before, they had guns on him in a public library before he could even close the lid on his machine, (which would have turned his machine off, and the disk would be encrypted.) catching him in the act, his machine on, the screen open meant that they could get all that they want. (because the police in the US cannot compel you to tell them your computers password, or provide encryption keys.)
Goodness gracious, I knew I was ignorant about VPN.....but I didn't know just HOW IGNORANT I was.
root probably has a lot of hands-on experience,
Yep, First, you're not ignorant, (I mean you're asking questions!)
And yes, I do work "in IT" (and by next year will have done for half my life!) - which means it is "literally" my job to know this stuff.
As AMD_man says: there are a ton of things online that will teach you this sort of stuff.
Most of what I know I learned for free by either reading it, or just asking people about it.
(and what I learned either during my education in school/college/university, or on vendor courses since leaving university. - I could have learned for free on the internet anyway.) - I'm not devaluing professional education there, just saying that you can learn for free.