Route Table Demo

In this guide, we walk through Amazon VPC route tables: inspecting the default table, creating custom tables, associating subnets, editing routes, and cleaning up resources.

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1. Setting Up a Demo VPC and Subnets

First, create a new VPC using the AWS Console or CLI:

• Name: vpcdemo
• IPv4 CIDR block: 10.0.0.0/16
• Enable IPv6: Yes

Next, add two subnets within vpcdemo:

1. Subnet One
   • IPv4 CIDR: 10.0.1.0/24
   • IPv6 CIDR: auto-assigned
2. Subnet Two
   • IPv4 CIDR: 10.0.2.0/24
   • IPv6 CIDR: auto-assigned

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2. Viewing the Default Route Table

When you create a VPC, AWS automatically generates a main route table. Any subnet without an explicit association uses this default table. Open the Route Tables page and select the default entry: Here you’ll see two default routes:

• 10.0.0.0/16 → local (IPv4 internal traffic)
• ::/0 → local (IPv6 internal traffic)

Under Subnet Associations, subnets without explicit associations are listed:

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3. Creating and Associating a Custom Route Table

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3.1 Create Route Table One

1. Navigate to Route Tables → Create route table.
2. Name: route-table-one
3. VPC: vpcdemo

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3.2 Associate Subnet One

1. Select the route-table-one entry.
2. Click Subnet Associations → Edit subnet associations.
3. Check Subnet One → Save.

Traffic originating in Subnet One now follows the rules in route-table-one.

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4. Adding a Second Custom Route Table

Repeat the process to isolate Subnet Two:

1. Create route table → Name: route-table-two → VPC: vpcdemo
2. Select route-table-two → Subnet Associations → Edit → Check Subnet Two → Save

This setup illustrates how:

• Public subnets can route via an Internet Gateway
• Private subnets remain isolated

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5. Editing Routes in a Route Table

To add or update routes:

1. Select a route table (e.g., route-table-one).
2. Go to Routes → Edit routes.
3. Click Add route:
   • Destination: 0.0.0.0/0 (all IPv4 traffic)
   • Target: select an Internet Gateway, NAT Gateway, etc.
4. Click Save changes.

Routes are evaluated by the most specific matching prefix to determine the next hop.

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6. Cleaning Up Resources

To avoid unnecessary charges, delete the vpcdemo VPC. AWS will automatically remove associated subnets and custom route tables.

1. Select vpcdemo → Actions → Delete VPC.
2. Confirm by typing delete → Delete.

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In this tutorial, you learned how to inspect AWS VPC route tables, create custom tables, associate subnets, modify routes, and clean up.

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References

• AWS VPC Documentation
• AWS Route Tables
• AWS IAM Best Practices