Interview Q&A / AWS & Cloud
AWS & Cloud interview questions
EC2, S3, Lambda, IAM and VPC basics, with when to pick which service.
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- How many usable IP addresses does a /24 subnet in an AWS VPC have?
A /24 has 256 addresses, but AWS reserves five in every subnet, so 251 are usable. The reserved ones are the network address, VPC router, DNS, one for future use, and the broadcast address.
BeginnerQuick answer1 min read - What is the difference between an internet gateway and a NAT gateway?
An internet gateway lets resources with public IPs in a public subnet talk to the internet in both directions. A NAT gateway lets private-subnet instances start outbound connections, such as updates, while blocking inbound connections from the internet.
BeginnerQuick answer1 min read