How to configure Firewall to route all traffic from L2TP VPN client to the remote site via MPLS VPN
03/26/2020 
13 
19370
DESCRIPTION:
How to configure Firewall to route all traffic from L2TP VPN client to the remote site via MPLS VPN tunnel.
RESOLUTION:
In the below scenario, outside laptop connects to Site A through L2TP VPN. Both Site A and Site B can access to Internet via WAN interface X1, while there is an MPLS VPN tunnel between these two sites. This article will describe how to route all traffic from terminal laptop to the remote Site B through MPLS VPN tunnel.
Step 2: Route all traffic of terminal laptop to Site A.
- Navigate to Users | LocalUsers | Click the Edit button of L2TP VPN user | Add group Trusted Users (Configured for L2TP) in the Groups tab | Add WAN RemoteAccess Networks in the VPN Access tab.
- Navigate to VPN | Settings page | Enable WAN Group VPN | Click the Edit button of WAN GroupVPN | Select This Gateway Only for option Allow Connections to: at Client tab | Tick options Set Default Route as this Gateway and also Apply VPN Access Control List.
Step 3 : Route all traffic of terminal laptop from Site A to Site B.
- Add a routing policy on the firewall of Site A. Go to Network | Routing | Click button Add.
- On site A, add a NAT policy to translate L2TP IP Pool addresses to the IP address visible on Site B (you can choose IP address of the interface connecting to MPLS tunnel ). Navigate to Network | NAT Policies | Click button Add.
Note: when browse NAT policies you will find there is a default NAT policy for L2TP IP Pool which was generated by system when configuring WAN GroupVPN. In order to ensure the policy you just created can be hit as default, y ou are required to change the Priority of the NAT policy you just added to be prior to the default NAT Policy by clicking Priority button. In this case, the priority for the policy is configured as 3. Step 4 : this step depends on the zone type of the interface connecting to MPLS VPN tunnel. If the type of the interface is LAN, you can ignore this step. If the interface is set as DMZ or WAN, you are required to add Access Rules (Firewall | Access Rules ) on Site B for WAN/DMZ to LAN and WAN to WAN access. While, when using WAN zone, you may also need to add a NAT policy to translate the IP address of MPLS VPN to the WAN primary IP address on site B.
How to test:
- On the mobile laptop, connect to the L2TP server of site A and ping any LAN subnet IP address of site B or Interet site.
- You can capture the packets on Site B to check whether the traffic has been routed.
Resolution for SonicOS 6.5
This release includes significant user interface changes and many new features that are different from the SonicOS 6.2 and earlier firmware. The below resolution is for customers using SonicOS 6.5 firmware.
In the below scenario, outside laptop connects to Site A through L2TP VPN. Both Site A and Site B can access to Internet via WAN interface X1, while there is an MPLS VPN tunnel between these two sites. This article will describe how to route all traffic from terminal laptop to the remote Site B through MPLS VPN tunnel.
How to configure:
Go to Manage > VPN > L2TP Server
Select Enable L2TP Server and click Configure as shown below:
Kepp alive should be set for 60 Secs.
Configure the Primary and Secondary DNS Server with the ip addresses of your internal DNS Servers.
Example:
- DNS Server 1: 10.190.202.200
- DNS Server 2: 10.102.1.51
Go to Manage > VPN > L2TP Server > L2TP Users
Step 2: Route all traffic of terminal laptop to Site A.
- Navigate to Manage | Users | LocalUsers & Groups, Click the Edit button of L2TP VPN user (If non existant please create a user)
- Add group Trusted Users (Configured for L2TP) in the Groups tab.
- Add WAN RemoteAccess Networks in the VPN Access tab.
- Navigate to Manage | VPN | Base Settings page
- Enable WAN Group VPN | Click the Edit button of WAN GroupVPN
- Select This Gateway Only for option Allow Connections to: at Client tab | Tick options Set Default Route as this Gateway and also Apply VPN Access Control List.
Step 3 : Route all traffic of terminal laptop from Site A to Site B.
- Add a routing policy on the firewall of Site A. Go to Manage| Network | Routing | Routing Policies | Click button Add.
- Source: L2TP IP Pool
- Destination: Any
- Service: Any
- Gateway: To SiteB Gateway
- Interface: Select interface connected to MPLS Tunnel
- Metric: 1
- On site A, add a NAT policy to translate L2TP IP Pool addresses to the IP address visible on Site B (you can choose IP address of the interface connecting to MPLS tunnel ).
- Navigate to Manage | Rules | NAT Policies | Click button Add.
Note: when browse NAT policies you will find there is a default NAT policy for L2TP IP Pool which was generated by system when configuring WAN GroupVPN. In order to ensure the policy you just created can be hit as default, y ou are required to change the Priority of the NAT policy you just added to be prior to the default NAT Policy by clicking Priority button. In this case, the priority for the policy is configured as 3. Step 4 : this step depends on the zone type of the interface connecting to MPLS VPN tunnel. If the type of the interface is LAN, you can ignore this step. If the interface is set as DMZ or WAN, you are required to add Access Rules (Manage | Rules | Access Rules ) on Site B for WAN/DMZ to LAN and WAN to WAN access. While, when using WAN zone, you may also need to add a NAT policy to translate the IP address of MPLS VPN to the WAN primary IP address on site B.
How to test:
- On the mobile laptop, connect to the L2TP server of site A and ping any LAN subnet IP address of site B or Interet site.
- You can capture the packets on Site B to check whether the traffic has been routed.
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