Networking jargon

🏗️ First: The Big Picture — Think of a VPC as a Neighborhood

In AWS:

VPC (Virtual Private Cloud) = Your private neighborhood
Subnets = Different streets in your neighborhood (public or private)
EC2 = Houses
ENI = The network interface card (NIC) on the house
EIP / Public IP = Street address the internet can see
Route Table = GPS that tells traffic where to go
IGW = Internet Gateway, your neighborhood’s front gate
NAT Gateway = Controlled backdoor for inside-only houses to reach the internet

Component	What It Does	Analogy
ENI	Elastic Network Interface — connects EC2 to network	Like a network card (Ethernet port) in your house
IGW	Internet Gateway — allows inbound/outbound internet	The main gate of your neighborhood
NAT Gateway	Allows private subnets to access internet outbound only	A valve that lets water out but blocks outside water
EIP	Elastic IP — static public IP	A permanent address you can take with you
Private IP	Internal IP inside VPC	House number inside the neighborhood
Public IP	Temporary public address (unless EIP)	Short-term rental address — can change
Route Table	Tells subnets how to reach other networks or the internet	The GPS / map used to find paths
Security Group	Controls who can knock on your door (stateful)	The bouncer checking IDs
NACL	Network ACL — subnet-level firewall (stateless)	The neighborhood fence