Peering connection basic error

Question

Hello,

When I tried to request a Peering Connection in same account, among 2 VPCs from different AZs, I got the below error in both AZs in Peering connections section -> Status field from Details. Could you please specify the cause ?

```
Failed due to incorrect VPC-ID, Account ID, or overlapping CIDR range
```
Update: Both VPCs have same CIDR range: 172.31.0.0/16

Thank you,  
Mihai ADAM

Matt-B · Answer

Hi There

The issue is that both VPC's have the same CIDR range which isnt allowed.

You cannot create a VPC peering connection between VPCs that have matching or overlapping IPv4 or IPv6 CIDR blocks.  See https://docs.aws.amazon.com/vpc/latest/peering/vpc-peering-basics.html

You do have some options to connect VPC's with overlapping CIDR ranges though, please take a look at this blog: https://aws.amazon.com/blogs/networking-and-content-delivery/connecting-networks-with-overlapping-ip-ranges/

Peering connection basic error

Relevant content