Public Subnet

What it is: A subnet where resources can reach the internet directly via an Internet Gateway route.

What it’s for:

• Host internet-facing resources like load balancers, bastion hosts, public web servers (when required).

Requirements (typical):

• Subnet route table includes `0.0.0.0/0 → IGW`.
• Instances often need a public IPv4 (or Elastic IP) to be reachable from internet (depending on setup).

Exam cues:

• “internet-facing ALB” → placed in public subnets.
• “public access” → IGW route exists.

Hard words:

• *internet-facing* /ˈɪntərnɛt ˈfeɪsɪŋ/: hướng Internet (public)
• *reachable* /ˈriːtʃəbl/: có thể truy cập tới