Security groups adalah firewall virtual yang mengontrol traffic inbound dan outbound ke resource AWS (seperti EC2 instances) — mendefinisikan port, protokol, dan sumber mana yang diizinkan. Mereka fundamental untuk keamanan jaringan AWS.
Apa yang dilakukan security groups
A SECURITY GROUP is a virtual firewall attached to resources (EC2, RDS, etc.):
→ INBOUND rules — what traffic can REACH the resource (port, protocol, source)
→ OUTBOUND rules — what traffic the resource can SEND OUT
→ only ALLOW rules (no explicit deny); everything not allowed is DENIED by default
→ STATEFUL — if inbound is allowed, the response is automatically allowed back
