VPC Troubleshooting:

New EC2 instances are not automatically being assigned a public IP address:

• Modify the Auto-Assign Public IP setting on the subnet.

NAT Gateway is configured but instances inside a private subnet still cannot download packages:

• Need to add 0.0.0.0/0 route to the NAT gateway on the route table for private subnet.

Traffic is not making it to the instances even though security group rules are correct:

• Check the Network Access Control Lists to ensure the proper ports from the proper sources are open. (also check your IGW and route table settings)

Error when attempting to attach multiple internet gateways to a VPC:

• Only one internet gateway can be attached to a VPC at any given time.

Error when attempting to attach multiple Virtual Private Gateways to a VPC:

• Only one Virtual Private Gateway can be attached to a VPC at any given time.

VPC Security Group (for EC2 instances) does not have enough rules for the required application:

• Assign the EC2 instance to multiple security groups.

Cannot SSH/communicate with resources inside of a private subnet:

• Either you have not setup a VPN, or you have not connected to an EC2 instance (Bastion Host) within the VPC to launch a connection from.

Successful site-to-site VPN connection but unable to access extended resources:

• Need to add on-premise routes to the Virtual Private Gateway route table.

Failure to create a VPC peering connection between two VPC's in different regions:

• Peering connection can only be created between two VPC's in the same region.