AWS VPC Configuration: 5 Kick-Yourself Mistakes

AWS VPC configuration: getting it right.

AWS VPC logoThe great thing about an AWS VPC is the incredible flexibility and security it offers. Amazon’s VPCs allow you to provision compute resources, like EC2 instances and RDS deployments, inside Amazon’s isolated virtual networks, giving you complete control over all inbound and outbound network traffic. You can select IP address ranges, subnet association, and route table and network gateway configuration. You’re really in control.

Here’s what’s great about the VPCs:

  • Since instances launched into an AWS VPC aren’t directly accessible from the internet, they are by default more secure.
  • VPCs simplify security, allowing seamless integration with ACLs, Routing rules, and security groups.
  • You can attach multiple network interfaces.
  • You can directly connect your on-premise network to an AWS VPC.
  • VPCs simplify secure, multi-tier web deployments (like connecting a public app to a private database server living in a private subnet).
  • Disaster recovery backup images built on VPC connectivity through private connections can make recovering mission-critical data simpler and more reliable.
  • Launch-dedicated instances running on hardware dedicated to a single customer gain additional isolation.

On the other hand…

As well-designed as VPCs are, they’re not bulletproof. Especially when human beings get involved. Since you should be aiming for absolute perfection for all your deployments, make sure that you avoid these configuration blunders:

Five AWS VPC config mistakes

  1. Poor subnet/CIDR Block planning: Administrators often fail to keep network compatibility and future needs in mind while designing their VPC subnets and CIDR blocks. Bearing in mind that AWS VPC subnet blocks, once assigned, can’t be modified, you should carefully calculate how many nodes each subnet might need. Remember: creating a /24 or /27 CIDR might not leave you enough addresses. Also, choosing, say, a 10.0.0.0/16 block for your VPC subnet when the local data center you want to connect to uses 10.0.26.0/24 won’t end happily.
  2. Public IP addresses: When you launch an instance into the public subnet of a nondefault VPC (using it’s default settings), it will not get a public IP or hostname the way it would use the old EC2-Classic. Once it’s created, the only way to make your instance publicly addressable is by assigning an elastic IP to the node. Elastic IPs are not free and, by default, you are limited to five per account (although you can always request more).
  3. Sharing Production and Development Environments: Putting all your staging, dev, and production environments into a single VPC will pretty much guarantee loads of confusion and endless security group and routing table conflicts.
  4. Not considering distributed redundancy for NAT instances: Smart admins always build High-Availability into their applications. But then some of them place their applications or database servers inside private subnets that will access remote services (S3, SQS, patches, and updates) through stand-alone NAT instances. When the NAT instance goes down, your whole application will break. Here’s a quick tutorial to build and configure a NAT Instance.
  5. Assuming an AWS VPC requires complex networking skills: VPCs are not switches. VPCs are not routers. VPCs are not firewalls. Even if they perform the work of all three of those hardware tools, VPCs are really software-defined networks (SDN). AWS designed them from the bottom up to be straightforward and uncomplicated. You do need to understand a few very basic networking concepts like routing, NAT, VPN, and ACL, but AWS itself does most of the heavy lifting.

Conclusion

If you’re still hosting your applications within EC2-Classic, you should seriously consider migrating to AWS VPC to leverage the huge benefits of VPC. But always stick with Best Practices…and think ahead!

And by the way, Cloud Academy has a full video course on AWS VPCs.

Avatar

Written by

Nitheesh Poojary

My professional IT career began nine years back when I was just out of my college. I worked with a great team as an infrastructure management engineer, managing hundreds of enterprise application servers. I found my passion when I got the opportunity to work with Cloud technologies: I'm addicted to AWS Cloud Services, DevOps engineering, and all the cloud tools and technologies that make engineers' lives easier. Currently, I am working as a Solution Architect in SixNines IT. We are an experienced team of engineers that have helped hundreds of customers move to the cloud responsibly. I have achieved 5 AWS certifications, happily helping fellow engineers across the globe through my blogs and answering questions in various forums.


Related Posts

Amanda Cross
Amanda Cross
— April 9, 2021

New Content: Platforms, Programming, and DevOps – Something for Everyone

This month our team of expert certification specialists released three new or updated learning paths, 16 courses, 13 hands-on labs, and four lab challenges! New content on Cloud Academy You can always visit our Content Roadmap to see what’s just released as well as what’s coming soon....

Read more
  • alibaba
  • AWS
  • Azure
  • DevOps
  • Google Cloud Platform
  • programming
  • Security
Luca Casartelli
Luca Casartelli
— March 31, 2021

Mastering AWS Organizations Service Control Policies

Service Control Policies (SCPs) are IAM-like policies to manage permissions in AWS Organizations. SCPs restrict the actions allowed for accounts within the organization making each one of them compliant with your guidelines. SCPs are not meant to grant permissions; you should consider ...

Read more
  • AWS
  • Organizations
  • SCP
Amanda Cross
Amanda Cross
— March 12, 2021

New Content: Focus on DevOps and Programming Content this Month

This month our team of expert certification specialists released 12 new or updated learning paths, 15 courses, 25 hands-on labs, and four lab challenges! New content on Cloud Academy You can always visit our Content Roadmap to see what’s just released as well as what’s coming soon. Ja...

Read more
  • alibaba
  • AWS
  • Azure
  • DevOps
  • Google Cloud Platform
  • programming
Amanda Cross
Amanda Cross
— February 12, 2021

New Content: Get Ready for the CISM Cert Exam & Learn About Alibaba, Plus All the AWS, GCP, and Azure Courses You Know You Can Count On

This month our team of intrepid certification specialists released five learning paths, seven courses, 19 hands-on labs, and three lab challenges!  One particularly interesting new learning path is Certified Information Security Manager (CISM) Foundations. After completing this learn...

Read more
  • alibaba
  • AWS
  • Azure
  • cism
  • DevOps
  • Google Cloud Platform
  • programming
Avatar
Cloud Academy Team
— January 31, 2021

Which Certifications Should I Get?

The old AWS slogan, “Cloud is the new normal” is indeed a reality today. Really, cloud has been the new normal for a while now and getting credentials has become an increasingly effective way to quickly showcase your abilities to recruiters and companies. With all that in mind, the s...

Read more
  • AWS
  • Azure
  • Certifications
  • Cloud Computing
  • Google Cloud Platform
Avatar
Andrew Larkin
— January 31, 2021

The 12 AWS Certifications: Which is Right for You and Your Team?

As companies increasingly shift workloads to the public cloud, cloud computing has moved from a nice-to-have to a core competency in the enterprise. This shift requires a new set of skills to design, deploy, and manage applications in cloud computing. As the market leader and most ma...

Read more
  • AWS
  • AWS Certifications
Avatar
Stuart Scott
— January 29, 2021

AWS Certified Solutions Architect Associate: A Study Guide

Want to take a really impactful step in your technical career? Explore the AWS Solutions Architect Associate certificate. Its new version (SAA-C02) was released on March 23, 2020. The AWS Solutions Architect - Associate Certification (or Sol Arch Associate for short) offers some ...

Read more
  • AWS
  • AWS Certifications
  • AWS Certified Solutions Architect Associate
Amanda Cross
Amanda Cross
— January 7, 2021

New Content: AWS Terraform, Java Programming Lab Challenges, Azure DP-900 & DP-300 Certification Exam Prep, Plus Plenty More Amazon, Google, Microsoft, and Big Data Courses

This month our Content Team continues building the catalog of courses for everyone learning about AWS, GCP, and Microsoft Azure. In addition, this month’s updates include several Java programming lab challenges and a couple of courses on big data. In total, we released five new learning...

Read more
  • AWS
  • Azure
  • DevOps
  • Google Cloud Platform
  • Machine Learning
  • programming
Avatar
Stuart Scott
— December 17, 2020

Where Should You Be Focusing Your AWS Security Efforts?

Another day, another re:Invent session! This time I listened to Stephen Schmidt’s session, “AWS Security: Where we've been, where we're going.” Amongst covering the highlights of AWS security during 2020, a number of newly added AWS features/services were discussed, including: AWS Audit...

Read more
  • AWS
  • AWS re:Invent
  • cloud security
Joe Nemer
Joe Nemer
— December 4, 2020

AWS re:Invent: 2020 Keynote Top Highlights and More

We’ve gotten through the first five days of the special all-virtual 2020 edition of AWS re:Invent. It’s always a really exciting time for practitioners in the field to see what features and services AWS has cooked up for the year ahead.  This year’s conference is a marathon and not a...

Read more
  • AWS
  • AWS Glue Elastic Views
  • AWS re:Invent
Bryony Harrower
Bryony Harrower
— November 6, 2020

WARNING: Great Cloud Content Ahead

At Cloud Academy, content is at the heart of what we do. We work with the world’s leading cloud and operations teams to develop video courses and learning paths that accelerate teams and drive digital transformation. First and foremost, we listen to our customers’ needs and we stay ahea...

Read more
  • AWS
  • Azure
  • content roadmap
  • GCP
Joe Nemer
Joe Nemer
— October 25, 2020

Excelling in AWS, Azure, and Beyond – How Danut Prisacaru Prepares for the Future

Meet Danut Prisacaru. Danut has been a Software Architect for the past 10 years and has been involved in Software Engineering for 30 years. He’s passionate about software and learning, and jokes that coding is basically the only thing he can do well (!). We think his enthusiasm shines t...

Read more
  • AWS
  • careers
  • champions
  • upskilling