Mastering AWS Network Security: In-
Depth Explanations, Best Practices,
and Essential Q&A latest update
1. Secure VPC Design
Explanation
A Virtual Private Cloud (VPC) is the foundational network layer in AWS.
Securing it involves:
Network Segmentation:
o Public Subnets: Host internet-facing resources (e.g., web
servers, load balancers) with controlled access via Security
Groups.
o Private Subnets: Isolate sensitive resources (e.g., databases,
application servers) with no direct internet access. Use NAT
Gateways for outbound traffic.
CIDR Planning:
o Use non-overlapping RFC 1918 ranges
(e.g., 10.0.0.0/16, 172.16.0.0/12) to avoid conflicts with on-
premises networks.
o Reserve IP space for future scalability (e.g., /16 allows 65k IPs).
Route Tables:
o Public Route Table: Directs traffic to/from the internet via
an Internet Gateway (IGW).
o Private Route Table: Routes traffic through a NAT Gateway for
controlled outbound access.
Best Practices
Disable default VPCs to enforce custom, secure configurations.
Use VPC Flow Logs to audit traffic and detect anomalies.
2. Security Groups (SGs) & Network ACLs (NACLs)
, Explanation
Security Groups:
o Stateful Firewalls: Track connection states (e.g., allow return
traffic automatically).
o Instance-Level: Attach to EC2 instances, RDS, or Elastic Load
Balancers.
o Least Privilege: Only allow necessary ports (e.g., 80/443 for
web traffic).
NACLs:
o Stateless Firewalls: Evaluate rules without tracking
connections.
o Subnet-Level: Apply to entire subnets (e.g., block malicious IP
ranges).
o Rule Ordering: Process rules in numerical order (e.g., deny rule
100 overrides allow rule 200).
Example Configuration
yaml
Copy
# Security Group allowing HTTPS
WebServerSG:
Type: AWS::EC2::SecurityGroup
Properties:
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 443
ToPort: 443
CidrIp: 0.0.0.0/0
# NACL blocking a malicious IP
BadIPNACL:
Depth Explanations, Best Practices,
and Essential Q&A latest update
1. Secure VPC Design
Explanation
A Virtual Private Cloud (VPC) is the foundational network layer in AWS.
Securing it involves:
Network Segmentation:
o Public Subnets: Host internet-facing resources (e.g., web
servers, load balancers) with controlled access via Security
Groups.
o Private Subnets: Isolate sensitive resources (e.g., databases,
application servers) with no direct internet access. Use NAT
Gateways for outbound traffic.
CIDR Planning:
o Use non-overlapping RFC 1918 ranges
(e.g., 10.0.0.0/16, 172.16.0.0/12) to avoid conflicts with on-
premises networks.
o Reserve IP space for future scalability (e.g., /16 allows 65k IPs).
Route Tables:
o Public Route Table: Directs traffic to/from the internet via
an Internet Gateway (IGW).
o Private Route Table: Routes traffic through a NAT Gateway for
controlled outbound access.
Best Practices
Disable default VPCs to enforce custom, secure configurations.
Use VPC Flow Logs to audit traffic and detect anomalies.
2. Security Groups (SGs) & Network ACLs (NACLs)
, Explanation
Security Groups:
o Stateful Firewalls: Track connection states (e.g., allow return
traffic automatically).
o Instance-Level: Attach to EC2 instances, RDS, or Elastic Load
Balancers.
o Least Privilege: Only allow necessary ports (e.g., 80/443 for
web traffic).
NACLs:
o Stateless Firewalls: Evaluate rules without tracking
connections.
o Subnet-Level: Apply to entire subnets (e.g., block malicious IP
ranges).
o Rule Ordering: Process rules in numerical order (e.g., deny rule
100 overrides allow rule 200).
Example Configuration
yaml
Copy
# Security Group allowing HTTPS
WebServerSG:
Type: AWS::EC2::SecurityGroup
Properties:
SecurityGroupIngress:
- IpProtocol: tcp
FromPort: 443
ToPort: 443
CidrIp: 0.0.0.0/0
# NACL blocking a malicious IP
BadIPNACL:
