You are previewing Programming Amazon Web Services.

Programming Amazon Web Services

Cover of Programming Amazon Web Services by James Murty Published by O'Reilly Media, Inc.
  1. Programming Amazon Web Services
    1. SPECIAL OFFER: Upgrade this ebook with O’Reilly
    2. A Note Regarding Supplemental Files
    3. Preface
      1. What’s in This Book?
      2. Ruby and Interactive Examples
      3. Conventions Used in This Book
      4. Using Code Examples
      5. Safari® Enabled
      6. How to Contact Us
      7. Acknowledgments
    4. 1. Infrastructure in the Cloud
      1. Amazon Web Services for Infrastructure
      2. Thinking Like Amazon
      3. Reality Check
      4. Interfaces: REST and Query Versus SOAP
    5. 2. Interacting with Amazon Web Services
      1. REST-Based APIs
      2. User Authentication
      3. Performing AWS Requests
    6. 3. S3: Simple Storage Service
      1. S3 Overview
      2. Interacting with S3
      3. Buckets
      4. Objects
      5. Alternative Hostnames
      6. Access Control Lists
      7. Server Access Logging (Beta)
      8. Signed URIs
      9. Distributing Objects with BitTorrent
    7. 4. S3 Applications
      1. Share Large Files
      2. Online Backup with AWS::S3
      3. S3 Filesystem with ElasticDrive
      4. Mediated Access to S3 with JetS3t
    8. 5. EC2: Elastic Compute Cloud (Beta)
      1. EC2 Overview
      2. Interacting with EC2
      3. Keypairs
      4. Network Security by IP
      5. Finding Amazon Machine Images
      6. Controlling Instances
      7. Log In to an Instance
      8. Security Groups
      9. Managing and Sharing AMIs
      10. Console Output and Instance Reboot
    9. 6. Using EC2 Instances and Images
      1. EC2 Instances in Detail
      2. Data Management in EC2
      3. Modifying an AMI
      4. Registering an AMI
      5. Create an AMI from Scratch
    10. 7. EC2 Applications
      1. Dynamic DNS
      2. On-Demand VPN Server with OpenVPN
      3. Web Photo Album with Gallery 2
    11. 8. SQS: Simple Queue Service
      1. SQS Overview
      2. Interacting with SQS
      3. Queues
      4. Messages
      5. Queue Attributes
      6. Queue Access Control
    12. 9. SQS Applications
      1. Messaging Simulator
      2. Distributed Application Services with BOTO
      3. Automated Management of EC2 Instance Pools with Lifeguard
    13. 10. FPS: Flexible Payments Service (Beta)
      1. FPS Overview
      2. Interacting with FPS
      3. Managing Your Tokens
      4. Acquiring Third-Party Tokens
      5. Pay Now Widgets
    14. 11. FPS Transactions and Accounts
      1. Performing FPS Transactions
      2. Account Management and Information
    15. 12. FPS Advanced Topics
      1. Gatekeeper Language Guide
      2. Micropayments with FPS
      3. Building a Marketplace Application
      4. Subscribing to FPS Event Notifications
    16. 13. SimpleDB (Beta)
      1. SimpleDB Overview
      2. Interacting with SimpleDB
      3. Domains
      4. Items and Attributes
      5. Representing Data in SimpleDB
      6. Performing Queries
      7. Stock Price Database: A Mini SimpleDB Application
    17. A. AWS Resources
      1. AWS Online Resources
      2. Client Tools
      3. API Libraries
      4. Third-Party AWS Solutions
    18. B. AWS API Error Codes
      1. S3: Simple Storage Service
      2. EC2: Elastic Compute Cloud
      3. SQS: Simple Queue Service
      4. FPS: Flexible Payments Service
      5. SimpleDB
    19. Index
    20. About the Author
    21. Colophon
    22. SPECIAL OFFER: Upgrade this ebook with O’Reilly
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Security Groups

The EC2 environment provides a network security mechanism that acts as a firewall for incoming connections. The environment does not allow network traffic to reach an instance unless that traffic has been explicitly permitted.

The network security firewall is managed using security groups, which are named collections of access rules that specify which incoming (ingress) network connections the EC2 environment should allow to pass through to running instances. Security groups only control inbound network traffic; they will not prevent outbound traffic.

Security groups can contain two kinds of rules: IP rules and group rules.

IP rules

IP access rules, also known as CIDR rules, control traffic originating from outside or inside the EC2 environment. These rules specify the kinds of IP network traffic that will be allowed based on three constraints:

  • Protocol (TCP, UDP, or ICMP)

  • Target port range

  • Originating IP address range

We discussed IP rules and the API operation that applies to them in more detail earlier on, in the section Allow IP Traffic.”

Group rules

Group access rules control traffic originating from other instances within the EC2 environment. These rules define permissions based on which security groups an instance belongs to, rather than its IP address. Group rules are much less granular than IP rules and will automatically allow incoming network traffic, using any protocol or port number, from an instance belonging to a permitted security group.

Group rules are a convenient ...

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