## Site-to-Site VPN
A Site-to-Site Virtual Private Network (VPN) establishes a secure, encrypted tunnel between your RunAtlas VPC and your local office, datacenter, or another cloud provider. This allows you to treat your RunAtlas resources as an extension of your existing network.
### Prerequisites
- A [[VPC|VPC]] with at least one Tier/Subnet.
- A **Public IP** attached to the VPC Gateway (Source NAT).
- Access to configure your local router/firewall (e.g., Cisco ASA, Juniper SRX, PfSense, OpenVPN).
### Configuration Steps
1. **Enable VPN Gateway**:
- Navigate to **Network > VPC**.
- Select your VPC.
- Click the **VPN Gateway** tab (or icon).
- **Create/Enable**: This assigns the VPN service to the VPC's **Source NAT IP**. Note this public IP.
2. **Create Customer Gateway**:
- Within the VPC view (or under **Network > VPN Customer Gateway** if available globally), click **Add Customer Gateway**.
- **Name**: e.g., "Office-HQ-Router".
- **Gateway**: The public IP of your office firewall.
- **CIDR**: The IP range of your local network (e.g., `192.168.1.0/24`).
- **IKE/ESP Policy**: Define your encryption (AES-256), hash (SHA-256), and DH Group (e.g., Group 14).
3. **Create VPN Connection**:
- Navigate to **VPN Connections** (often a tab within the VPC or a sidebar item).
- Click **Create VPN Connection**.
- Select the **VPN Gateway** (your VPC) and the **Customer Gateway** (your office).
- **Passive/Active**: Usually checks "Passive" if the office side initiates the connection.
- **Preshared Key (PSK)**: Copy the generated key (or provide one).
### Local Configuration Example (Generic)
On your firewall:
- **Remote Gateway**: RunAtlas Public IP.
- **Remote Subnet**: RunAtlas VPC CIDR (e.g., `10.0.0.0/16`).
- **Local ID**: Your Firewall Public IP.
- **Preshared Key**: The key generated above.
- **Phase 1**: AES-256, SHA-256, DH2. Lifetime 28800.
- **Phase 2**: AES-256, SHA-256, PFS (optional). Lifetime 3600.
### Verification
Once configured on both sides:
1. Initiate traffic from your local network to an instance in the VPC.
2. Check the **Status** in the RunAtlas console (should turn **Green/Connected**).
3. Verify routing tables in your VPC route traffic destined for your office (`192.168.1.0/24`) through the VPN Gateway.
### Troubleshooting
- **Check Logs**: Review firewall logs for Phase 1 (IKE) or Phase 2 (IPsec) negotiation errors.
- **Mismatched Proposals**: Ensure encryption algorithms match exactly on both ends.
- **Firewall Rules**: Verify UDP 500, UDP 4500, and ESP (Protocol 50) are allowed on both public IPs.