VPC/CIDR IPv4 issue


Hello, Good day. Just started learning how to write IAAC on Cloud Formation using my text editor and I noticed something I don't understand.

Scenario 1 : If i create a VPC with an IPv4 CIDR ( it rejects on the AWS console as invalid.

Scenario 2 : But if i run it as IAAC (Cloud formation) on a connected text editor, it corrects the mistake and works but the error remains in the CFN template


I have screenshots incase this is needed.

Thank you

已提問 2 年前檢視次數 352 次
1 個回答

This is because CloudFormation corrects the VPC CIDR to its canonical form. See https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-ec2-vpc.html

CidrBlock The IPv4 network range for the VPC, in CIDR notation. For example, We modify the specified CIDR block to its canonical form; for example, if you specify, we modify it to

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已回答 2 年前
profile pictureAWS
已審閱 2 年前
  • This explains it quite well. Thank you very much.

  • Hello, does anyone has a human-readable reply? The answer is unclear to dummies like me and the URL quoted is not working. What is wrong with How should it be written???

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