NetworkLayer IP Routing
OSI Layer 3: IP addressing, routing tables, NAT — how packets actually find their way between hosts, underneath VPC/subnetting's AWS-specific config.
Why we need this / what value this brings
Misrouted or misconfigured routing (a route table pointing the wrong way, a missing NAT gateway) is a classic cause of 'why can't this private resource reach the internet' incidents.
When to use this
Whenever provisioning or debugging connectivity between subnets, or between a private resource and the internet.
How to use or implement this
Trace the actual path a packet would take (route table → NAT/IGW → destination) rather than guessing from security group rules alone — they operate at different layers.
Research questions
- What's the difference between a route table entry and a security group rule — which layer does each operate at?
- How does NAT (in a NAT gateway) let a private-subnet resource reach the internet without being directly reachable from it?
Empty folder — drop notes, links, and findings here as you research.