Networking
Modified 2026-10-11
OSI Model
Packets and Frames
A frame (layer 2) doesn't understand an IP address, while packets can.
TCP/IP
UDP/IP
IP Addresses
The subnet mask is required to understand which part of the ip address refers to the network, and which part refers to the hosts. It's also used to determine if a packet can be delivered using the local network, or if it needs to communicate to another network of hosts.
For example: 133.33.3.7, with a subnet mask of 255.255.0.0 or /16 defines 133.33 as the network, while 3.7 refers to a specific host.
NAT (Network Address Translation)
- static NAT => private ip addresses are assigned a public one (1:1), this how the AWS gateway operates
- dynamic NAT => private ip addresses are temporarily allocated an ip from the public ip pool (1:1-of-pool)
- PAT (Port Address Translation) => uses ports on public ip to map to an ip in the private network