In Amazon Web Services, IAM (Identity and Access Management) is a web service that helps you securely control access to AWS resources. IAM allows you to create and manage AWS users, groups, and permissions, ensuring that only authorized individuals or systems can access your resources and perform certain actions.
What IAM is:
User and Identity Management:
IAM enables you to create individual IAM users (representing real people or services) with their own credentials (username/password, access keys). You can then assign permissions to these users to control what actions they can perform on specific AWS resources.
Role Management:
You can define IAM roles, which are like sets of permissions, and then assign these roles to AWS services or users. This is useful when services (like EC2 instances) or users need to perform certain tasks without requiring direct access to AWS account credentials.
Permissions and Policies:
IAM allows you to set permissions using policies that specify what actions can be performed on which resources. Policies are written in JSON and define what a user, group, or role can or cannot do.
Access Control:
With IAM, you can restrict access to resources based on certain criteria (like user roles, time, or source IP addresses) and establish fine-grained access control.
Multi-factor Authentication (MFA):
IAM supports enabling MFA for an added layer of security. This ensures that users need to authenticate using both a password and a second factor (e.g., an MFA token) for sensitive actions.
Federated Access:
IAM allows for federated access, meaning users from external identity providers (e.g., Google, Active Directory) can access your AWS resources without having an IAM user in your account.
What IAM is not:
A way to manage the actual AWS resources:
IAM itself does not manage or control resources like EC2 instances, S3 buckets, or RDS databases. It only manages who can access these resources and what they can do with them. Resource provisioning and management are done outside IAM, using services like EC2, S3, Lambda, etc.
A Monitoring or Logging Service:
While IAM defines access permissions, it doesn't provide direct monitoring or auditing. However, you can use services like AWS CloudTrail to log and monitor IAM activity, such as who accessed which resources.
An Encryption Service:
IAM does not handle encryption directly. However, IAM can control who has access to encryption keys managed by services like AWS Key Management Service (KMS), which handles actual encryption.
A Service for Managing Billing or Payments:
IAM does not control or manage billing aspects of AWS usage. For billing and cost management, you would use the AWS Cost Management services.
A Replacement for Network Security:
IAM is about managing user and role permissions, not about network security, which is handled by other services like VPC (Virtual Private Cloud), Security Groups, and Network Access Control Lists (NACLs).
In short, IAM helps you control "who" can access your AWS resources and "what" they can do with them, but it does not manage the resources themselves or other aspects like billing or network configuration.
