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AWS EC2: adding IP from a separate private block

ba flag

I have an existing VPC with a CIDR in the 10.0.0.0/16 block.

I now have to create a VPN connection to an external service, who want us to use IPs in 192.168.0.0/16 block.

Unfortunately, AWS does not allow mixing these two blocks in a single VPC, otherwise adding a new CIDR block would have been an easy solution.

Short of creating a new VPC and migrating services, what are the options to achieve this? Ideally with no additional costs.

Thanks

/edit to add link

Tim avatar
gp flag
Tim
One option is to add an additional CIDR range to your VPC or set up another VPC, then set up a proxy in the new subnet. I suspect there are many other solutions but that's the first one that comes to mind https://aws.amazon.com/about-aws/whats-new/2017/08/amazon-virtual-private-cloud-vpc-now-allows-customers-to-expand-their-existing-vpcs/
NullPointer avatar
ba flag
What type of proxy? Any links would be appreciated. AWS does not allow adding "CIDR blocks from other RFC 1918 ranges". Question updated with link.
Tim avatar
gp flag
Tim
Ah, that's interesting that you can't add two of that type of block, never tried that. Proxy type depends what you're trying to achieve, you've not given much detail.
NullPointer avatar
ba flag
All I was trying to do was just add another site-to-site VPN. Ended up migrating to a new VPC, but surely, there must be an easier way.
Tim avatar
gp flag
Tim
The requirement for a specific CIDR range inside your VPC from whoever you're peering with is unusual. What I would've done would've depended on the peering reason. e.g. If you simply needed to access a web service you could put in another small VPC with an Apache proxy.
sa flag
If the VPN client is on an EC2 instance, VPC doesn't know about it, so it can use whatever address you want. (If the VPC can be directly connected to a VPN - is that a thing? then of course it does matter)
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