What it is: A set of routing rules that decide where network traffic goes.

What it’s for:

• Send traffic to IGW, NAT, VPC endpoints, peering, etc.
• Define public vs private subnets through default routes.

Key ideas:

• Each subnet is associated with one route table (main or custom).
• The most important route in exams:
  • `0.0.0.0/0` = “default route” (all IPv4 destinations).

Exam cues:

• “make subnet public” → add `0.0.0.0/0 → IGW`.
• “private subnet outbound internet” → `0.0.0.0/0 → NAT`.

Hard words:

• *routing* /ˈruːtɪŋ/: định tuyến
• *destination* /ˌdestɪˈneɪʃn/: đích đến
• *default route* /dɪˈfɔːlt ruːt/: tuyến mặc định