A policy-based VPN creates an IPsec tunnel and a policy that specifies how traffic uses it. When you use a policy-based VPN, you must update the routing tables on both ends of the network when new routes are added.
Policy-based VPNs in your VMware Cloud on AWS GovCloud SDDC use an IPsec protocol to secure traffic. To create a policy-based VPN, you configure the local (SDDC) endpoint, then configure a matching remote (on-premises) endpoint. Because each policy-based VPN must create a new IPsec security association for each network, an administrator must update routing information on premises and in the SDDC whenever a new policy-based VPN is created. A policy-based VPN can be an appropriate choice when you have only a few networks on either end of the VPN, or if your on-premises network hardware does not support BGP (which is required for route-based VPNs).
If your SDDC includes both a policy-based VPN and a route-based VPN, connectivity over the policy-based VPN will fail if the route-based VPN advertises the default route (0.0.0.0/0) to the SDDC.
- Log in to the VMware Cloud on AWS GovCloud at https://www.vmc-us-gov.vmware.com/.
- Select .
- Click ADD VPN and give the new VPN a Name and optional Description.
- Select a Local IP Address from the drop-down menu.
- If this SDDC is member of an SDDC group or has been configured to use AWS Direct Connect, select the private IP address to have the VPN use that connection rather than a connection over the Internet. Note that VPN traffic over Direct Connect or VMware Managed Transit Gateway (VTGW) is limited to the default MTU of 1500 bytes even if the link supports a higher MTU. See Configure Direct Connect to a Private Virtual Interface for SDDC Management and Compute Network Traffic.
- Select the public IP address if you want the VPN to connect over the Internet.
- Enter the Remote Public IP address of your on-premises gateway.
The address must not already be in use for another VPN. VMware Cloud on AWS GovCloud uses the same public IP for all VPN connections, so only a single VPN connection (Route-based, Policy-based, or L2VPN) can be created to a given remote public IP. This address must be reachable over the Internet if you specified a public IP in Step 4. If you specified a private IP, it must be reachable over Direct Connect to a private VIF. Default gateway firewall rules allow inbound and outbound traffic over the VPN connection, but you must create firewall rules to manage traffic over the VPN tunnel.
- (Optional) If your on-premises gateway is behind a NAT device, enter the gateway address as the Remote Private IP.
This IP address must match the local identity (IKE ID) sent by the on-premises VPN gateway. If this field is empty, the Remote Public IP field is used to match the local identity of the on-premises VPN gateway.
- Specify the Remote Networks that this VPN can connect to.
This list must include all networks defined as local by the on-premises VPN gateway. Enter each network in CIDR format, separating multiple CIDR blocks with commas.
- Specify the Local Networks that this VPN can connect to.
This list includes all routed compute networks in the SDDC, as well as the entire Management network and the appliance subnet (a subset of the Management network that includes vCenter and other management appliances, but not the ESXi hosts). It also includes the CGW DNS Network, a single IP address used to source requests forwarded by the CGW DNS service.
- Configure Advanced Tunnel Parameters.
Option Description Tunnel Encryption Select a Phase 2 security association (SA) cipher that is supported by your on-premises VPN gateway. Tunnel Digest Algorithm Select a Phase 2 digest algorithm that is supported by your on-premises VPN gateway.Note:
If you specify a GCM-based cipher for Tunnel Encryption, set Tunnel Digest Algorithm to None. The digest function is integral to the GCM cipher.
Perfect Forward Secrecy Enable or Disable to match the setting of your on-premises VPN gateway. Enabling Perfect Forward Secrecy prevents recorded (past) sessions from being decrypted if the private key is ever compromised. IKE Encryption Select a Phase 1 (IKE) cipher that is supported by your on-premises VPN gateway. IKE Digest Algorithm Select a Phase 1 digest algorithm that is supported by your on-premises VPN gateway. The best practice is to use the same algorithm for both the IKE Digest Algorithm and the Tunnel Digest Algorithm.Note:
If you specify a GCM-based cipher for IKE Encryption, set IKE Digest Algorithm to None. The digest function is integral to the GCM cipher. You must use IKE V2 if you use a GCM-based cipher.
- Specify IKE V1 to initiate and accept the IKEv1 protocol.
- Specify IKE V2 to initiate and accept the IKEv2 protocol. You must use IKEv2 if you have specified a GCM-based IKE Digest Algorithm.
- Specify IKE FLEX to accept either IKEv1 or IKEv2 and then initiate using IKEv2. If IKEv2 initiation fails, IKE FLEX will not fall back to IKEv1.
Diffie Hellman Select a Diffie Hellman group that is supported by your on-premises VPN gateway. This value must be identical for both ends of the VPN tunnel. Higher group numbers offer better protection. The best practice is to select group 14 or higher. Preshared Key Enter a preshared key used by both ends of the tunnel to authenticate with each other.
The string has a maximum length of 128 characters.
Connection Initiation Mode Connection initiation mode defines the policy used by the local endpoint in the process of tunnel creation. The following modes are available.
- The default value. In this mode, the local endpoint initiates VPN tunnel creation and responds to incoming tunnel setup requests from the peer gateway.
- On Demand
- In this mode, the local endpoint initiates VPN tunnel creation after the first packet matching the policy rule is received. It also responds to the incoming initiation request.
- Respond Only
- In this mode, the VPN never initiates a connection. The peer site always initiates the connection request and the local endpoint responds to that connection request.
TCP MSS Clamping To reduce the maximum segment size (MSS) payload of the TCP session during the IPsec connection, enable TCP MSS Clamping, select the TCP MSS direction value, and optionally set the TCP MSS Value. See Understanding TCP MSS Clamping in the NSX-T Data Center Administration Guide.
- (Optional) Tag the VPN.
See Add Tags to an Object in the NSX-T Data Center Administration Guide for more information about tagging NSX-T objects.
- Click SAVE.
- Click DOWNLOAD CONFIG to download a file that contains VPN configuration details. You can use these details to configure the on-premises end of this VPN.
- Click VIEW STATISTICS to view packet traffic statistics for this VPN. See Create a Policy-Based VPN.
What to do next
Create or update firewall rules as needed. To allow traffic through the policy-based VPN, specify Internet Interface in the Applied to field.