(12-07-2016, 03:38 AM)z3bra Wrote: what's a MAC address, an IP address, a netmask, how do they work together? What's a switch, a router, how do they know where to send packets?

Okay, I'll try to answer these without searching the internet. Phew.

MAC address: a (normally) device specific address, 48 bit long, set by the manufacturer. Can be changed,
normally shouldn't, is mostly used for authentication. Only the next router knows it.

IP address: IP addresses are used within the TCP/IP protocol to establish connections. IPv4 addresses are 32 bit long, IPv6 addresses
are 128 bit long (we are having a problem because we haven't got enough IPv4 addresses left). IPv4 addresses are mostly
dynamic, so every device is assigned an IP address with DHCP to avoid IPv4 address collisions. IPv6 doesn't need DHCP because
collisions are highly unlikely (the IPv6 address is generated via the MAC address and some device specific stuff).
IP addresses are hierarchical, which means that every network can have a sub-network. And here we get to the

netmask: a simple description of how big a subnet of a certain router is. For example, Apple has got a whole /24 network, meaning
that they can use every IP-address which begins with a 17 (17.1.1.1 for example) (source: https://www.xkcd.com/195/). IPv6 has the same
principle.

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[To be continued]