SSL VPN with RADIUS on FortiAuthenticator

This is a sample configuration of SSL VPN that uses FortiAuthenticator as a RADIUS authentication server.

Sample topology

Sample configuration

WAN interface is the interface connected to ISP. This example shows static mode. You can also use DHCP or PPPoE mode. The SSL VPN connection is established over the WAN interface.

To configure FortiAuthenticator using the GUI:

1. Create a user on the FortiAuthenticator.
   1. On the FortiAuthenticator, go to Authentication > User Management > Local Users to create a user sslvpnuser1.
   2. Enable Allow RADIUS authentication and click OK to access additional settings.
   3. Go to Authentication > User Management > User Groups to create a group sslvpngroup.
   4. Add sslvpnuser1 to the group by moving the user from Available users to Selected users.
2. Create the RADIUS client (FortiGate) on the FortiAuthenticator.
   1. On the FortiAuthenticator, go to Authentication > RADIUS Service > Clients to add the FortiGate as a RADIUS client OfficeServer).
   2. Enter the FortiGate IP address and set a Secret.

      The secret is a pre-shared secure password that the FortiGate uses to authenticate to the FortiAuthenticator.

   3. Set Realms to local | Local users.

To configure SSL VPN using the GUI:

1. Configure the interface and firewall address. The port1 interface connects to the internal network.
   1. Go to Network > Interfaces and edit the wan1 interface.
   2. Set IP/Network Mask to 172.20.120.123/255.255.255.0.
   3. Edit port1 interface and set IP/Network Mask to 192.168.1.99/255.255.255.0.
   4. Click OK.
   5. Go to Firewall & Objects > Address and create an address for internet subnet 192.168.1.0.
2. Create a RADIUS user and user group .
   1. On the FortiGate, go to User & Device > RADIUS Servers to create a user to connect to the RADIUS server (FortiAuthenticator).
   2. For Name, use FAC-RADIUS.
   3. Enter the IP address of the FortiAuthenticator, and enter the Secret created above.
   4. Click Test Connectivity to ensure you can connect to the RADIUS server.
   5. Select Test User Credentials and enter the credentials for sslvpnuser1.

      The FortiGate can now connect to the FortiAuthenticator as the RADIUS client.

   6. Go to User & Device > User Groups and click Create New to map authenticated remote users to a user group on the FortiGate.
   7. For Name, use SSLVPNGroup.
   8. In Remote Groups, click Add.
   9. In the Remote Server dropdown list, select FAC-RADIUS.
   10. Leave the Groups field blank.
3. Configure SSL VPN web portal.
   1. Go to VPN > SSL-VPN Portals to edit the full-access portal.

      This portal supports both web and tunnel mode.

   2. Disable Enable Split Tunneling so that all SSL VPN traffic goes through the FortiGate.
4. Configure SSL VPN settings.
   1. Go to VPN > SSL-VPN Settings.
   2. Select the Listen on Interface(s), in this example, wan1.
   3. Set Listen on Port to 10443.
   4. Set Server Certificate to the authentication certificate.
   5. Under Authentication/Portal Mapping, set default Portal web-access for All Other Users/Groups.
   6. Create new Authentication/Portal Mapping for group sslvpngroup mapping portal full-access.
5. Configure SSL VPN firewall policy.
   1. Go to Policy & Objects > IPv4 Policy.
   2. Fill in the firewall policy name. In this example, sslvpn certificate auth.
   3. Incoming interface must be SSL-VPN tunnel interface(ssl.root).
   4. Set the Source Address to all and Source User to sslvpngroup.
   5. Set the Outgoing Interface to the local network interface so that the remote user can access the internal network. In this example: port1.
   6. Set Destination Address to the internal protected subnet 192.168.1.0.
   7. Set Schedule to always, Service to ALL, and Action to Accept.
   8. Enable NAT.
   9. Configure any remaining firewall and security options as desired.
   10. Click OK.

To configure SSL VPN using the CLI:

1. Configure the interface and firewall address.

   config system interface 
       edit "wan1"
           set vdom "root"
           set ip 172.20.120.123 255.255.255.0
       next
   end

2. Configure internal interface and protected subnet, then connect the port1 interface to the internal network.

   config system interface
       edit "port1"
           set vdom "root"
           set ip 192.168.1.99 255.255.255.0
       next
   end
   config firewall address
       edit "192.168.1.0"
           set subnet 192.168.1.0 255.255.255.0
       next
   end

3. Create a RADIUS user and user group.

   config user radius
       edit "FAC-RADIUS"
           set server "172.20.120.161"
           set secret <FAC client secret>
       next
   end
   
   config user group
       edit "sslvpngroup"
           set member "FAC-RADIUS"
       next
   end

4. Configure SSL VPN web portal.

   config vpn ssl web portal
       edit "full-access"
           set tunnel-mode enable
           set web-mode enable
           set ip-pools "SSLVPN_TUNNEL_ADDR1"
           set split-tunneling disable
        next
   end

5. Configure SSL VPN settings.

   config vpn ssl settings
       set servercert "server_certificate"
       set tunnel-ip-pools "SSLVPN_TUNNEL_ADDR1"
       set source-interface "wan1"
       set source-address "all"
       set default-portal "web-access"
       config authentication-rule
           edit 1
               set groups "sslvpngroup"
               set portal "full-access"
           next        
   end

6. Configure one SSL VPN firewall policy to allow remote user to access the internal network.

   config firewall policy 
       edit 1
           set name "sslvpn web mode access"
           set srcintf "ssl.root"
           set dstintf "port1"
           set srcaddr "all"
           set dstaddr "192.168.1.0"
           set groups “sslvpngroup”
           set action accept
           set schedule "always"
           set service "ALL"
           set nat enable
       next
   end

To see the results of web portal:

1. From a remote device, use a web browser to log into the SSL VPN web portal http://172.20.120.123:10443.
2. Log in using the sslvpnuser1 credentials.
3. On the FortiGate, go to Monitor > SSL-VPN Monitor to confirm the user connection.

To see the results of tunnel connection:

1. Download FortiClient from www.forticlient.com.
2. Open the FortiClient Console and go to Remote Access > Configure VPN.
3. Add a new connection.
   • Set the connection name.
   • Set Remote Gateway to 172.20.120.123.
4. Select Customize Port and set it to 10443.
5. Save your settings.
6. Log in using the sslvpnuser1 credentials and check that you are logged into the SSL VPN tunnel.

To check the SSL VPN connection using the GUI:

1. Go to VPN > Monitor > SSL-VPN Monitor to verify the user’s connection.
2. Go to Log & Report > Forward Traffic to view the details of the SSL VPN traffic.

To check the web portal login using the CLI:

get vpn ssl monitor
SSL VPN Login Users:
 Index   User          Auth Type    Timeout    From           HTTP in/out  HTTPS in/out
 0       sslvpnuser1   1(1)         229        10.1.100.254   0/0          0/0

SSL VPN sessions:
 Index   User    Source IP      Duration        I/O Bytes       Tunnel/Dest IP 

To check the tunnel login using the CLI:

get vpn ssl monitor
SSL VPN Login Users:
 Index   User          Auth Type   Timeout    From           HTTP in/out  HTTPS in/out
 0       sslvpnuser1   1(1)        291        10.1.100.254   0/0          0/0

SSL VPN sessions:
 Index   User          Source IP      Duration     I/O Bytes      Tunnel/Dest IP 
 0       sslvpnuser1   10.1.100.254   9            22099/43228    10.212.134.200