How to control / restrict traffic over a site to site VPN tunnel using Access Rules

04/12/2021 872 21178

DESCRIPTION:

VPN: How to control / restrict traffic over a site to site VPN tunnel using Access Rules (SonicOS Enhanced)

This article illustrates how to restrict traffic to a particular IP Address and /or a Server over a site to site VPN tunnel. This way of controlling VPN traffic can be achieved by Access Rules.

For this scenario it is assumed that a site to site VPN tunnel between an NSA 2700 and a TZ 470 has been established and the tunnel up with traffic flowing both ways.

Now, all traffic from the the hosts behind the TZ 470 should be blocked except Terminal Services (RDP traffic to a Terminal Server behind the NSA 2700). 

On the other hand, the hosts behind the NSA 2700 should be able to access everything behind the TZ 470 . The configuration of each firewall is the following:

RESOLUTION:

Resolution for SonicOS 7.X

This release includes significant user interface changes and many new features that are different from the SonicOS 6.5 and earlier firmware. The below resolution is for customers using SonicOS 7.X firmware.

1. Login to the SonicWall Management Interface on the NSA 2700 device.
2. Click Object in the top navigation menu
3. Navigate to the Match Objects |Addresses . Create a new Address Object for the Terminal Server IP Address 192.168.1.2. 
       
   
   
4. Navigate to the Policy | Rules and policies | Access Rules page.
5. Select From VPN To LAN as shown in the screenshot. 
   
   
   
   
   
   
6. Create an Allow rule with Source as the address object for the Remote Site(Destination Network), Destination as the address object for the Terminal Server IP Address and Service as Terminal Services.
   

How to Test:

• From a host behind the TZ 470 , RDP to the Terminal Server IP 192.168.1.2.
• Pinging other hosts behind the NSA 2700 should fail.
• Likewise, hosts behind the NSA 2700 will be able to ping all hosts behind the TZ 470 .

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.

1. Login to the SonicWall Management Interface on the NSA 2600 device.
2. Click Manage in the top navigation menu
3. Navigate to the Policies | Objects | Address Objects page. Create a new Address Object for the Terminal Server IP Address 192.168.1.2.
   
   
   
4. Navigate to the Policies | Rules | Access Rules page.
5. Select From VPN To LAN as shown in the screenshot
   
   
   
6. Ceate a Deny rule blocking all traffic from the remote site with details as per the screenshot. This will override the auto-created allow rule.
   
   
7. Create an Allow rule with Source as the address object for the Remote Site, Destination as the address object for the Terminal Server IP Address and Service as Terminal Services.
   

How to Test:

• From a host behind the TZ 600 , RDP to the Terminal Server IP 192.168.1.2.
• Pinging other hosts behind the NSA 2600 should fail.
• Likewise, hosts behind the NSA 2600 will be able to ping all hosts behind the TZ 600 .

Resolution for SonicOS 6.2 and Below

The below resolution is for customers using SonicOS 6.2 and earlier firmware. For firewalls that are generation 6 and newer we suggest to upgrade to the latest general release of SonicOS 6.5 firmware.

1. Login to the SonicWall Management Interface.
2. Navigate to the Network | Address Objects page.
3. Create a new Address Object for the Terminal Server IP Address 192.168.1.2.
   
   
   
4. Navigate to the Firewall | Access Rules page.
5. Select From VPN | To LAN from the drop-down list or matrix.
6. Create a Deny rule blocking all traffic from the remote site with details as per the screenshot. This will override the auto-created allow rule.
7. Create an Allow rule with Source as the address object for the Remote Site, Destination as the address object for the Terminal Server IP Address and Service as Terminal Services.
   

How to Test:

• From a host behind the TZ 600 , RDP to the Terminal Server IP 192.168.1.2.
• Pinging other hosts behind the NSA 2600 should fail.
• Likewise, hosts behind the NSA 2600 will be able to ping all hosts behind the TZ 600 .