Cloud VPN with Public IP

Google Cloud Compute Infrastructure
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Hi,

We need to set up a classic VPN tunnel so that packets arriving through the tunnel have an external source IP address.

Creating this VPN works fine, but the other side is seeing our traffic coming from it’s internal IP in range 10.0.0.0/8.

What change is necessary so the partner sees our packets coming from the hosts external IP address?

Appreciate any feedback!

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Hi @freemae ,

By the looks of it, you wanted to configure your VPN to use a specific external source IP address for the traffic arriving through the VPN tunnel. You may need to set up Source NAT (SNAT) on your GCP side to translate the source IP address to the desired external IP address.

You can follow these steps below to configure SNAT:

  1. Go to the Cloud NAT page in the Google Cloud Console.
  2. Click “Create NAT” and provide a name for the Cloud NAT configuration.
  3. Choose the region where your VPN gateway is located.
  4. Choose the VPC network that your VPN is connected to. Select the subnet(s) that you want to perform NAT on.
  5. Specify the source and destination IP ranges for which you want to perform NAT. In this case, the source IP range would be the internal IP addresses of your VMs, and the destination IP range would be the IP range on the other side of the VPN.
  6. Choose the Translation target as the external IP address that you want to use for the translated packets.
  7. Ensure that the route for the destination IP range on the other side of the VPN points to the Cloud NAT configuration.

Once done, the source IP address of packets originating from your VMs in the specified subnet should be translated to the specified external IP address when they traverse the VPN tunnel.

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Hi Marvin,

Can you elaborate more where we can find this configuration in your step number 6 to set the translation IP address? Cant find it…

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