Step 1: Identify correct command for Network ACL inbound rule
The command to add an inbound rule is 'create-network-acl-entry' with '--ingress' flag.
Step 2: Verify parameters
Rule number, protocol TCP, port range 443, CIDR 0.0.0.0/0, and action allow are correctly specified in aws ec2 create-network-acl-entry --network-acl-id acl-12345678 --ingress --rule-number 100 --protocol tcp --port-range From=443,To=443 --cidr-block 0.0.0.0/0 --rule-action allow.
Step 3: Eliminate incorrect options
aws ec2 authorize-security-group-ingress --group-id sg-12345678 --protocol tcp --port 443 --cidr 0.0.0.0/0 is for Security Groups, C uses '--egress' (outbound), and D uses a non-existent command 'modify-network-acl-entry'.
Final Answer:
Option A -> Option A
Quick Check:
Use 'create-network-acl-entry' with '--ingress' for inbound rules [OK]
Quick Trick:Use create-network-acl-entry with --ingress for inbound ACL rules [OK]
Common Mistakes:
MISTAKES
Using Security Group commands instead of Network ACL commands
Confusing ingress and egress flags
Using non-existent CLI commands
Master "Security Groups and Network ACLs" in AWS
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