Captive Portal Security

Captive portal security provides an access point that initially appears open. The wireless client can connect to the AP with no security credentials. The AP responds to the client's first HTTP request with a web page requesting user name and password. Until the user enters valid credentials, no communication beyond the AP is permitted.

The captive portal can be hosted on the FortiGate unit, or on an external authentication server.

This section includes the following topics:

• Captive portal types
• Configuring a FortiGate captive portal
• Configuring an external captive portal
• Configuring MAC Bypass for captive portal

Captive portal types

The WiFi captive portal types are available depending on your SSID traffic mode:

Name	Description	Traffic Mode
Available in the GUI and CLI
Authentication	Until the user enters valid credentials, no communication beyond the AP is permitted.	Tunnel Bridge
Disclaimer + Authentication	Immediately after successful authentication, the portal presents the disclaimer page—an acceptable use policy or other legal statement—to which the user must agree before proceeding.	Tunnel
Disclaimer Only	The portal presents the disclaimer page—an acceptable use policy or other legal statement—to which the user must agree before proceeding. The authentication page is not presented.	Tunnel
Email Collection	The portal presents a page requesting the user’s email address, for the purpose of contacting the person in future. This is often used by businesses who provide free WiFi access to their customers. The authentication page is not presented. To enable Email Collection, go to System > Feature Visibility, and enable Email Collection, then select Email Collection for Portal Type.	Tunnel
Available in CLI only
cmcc	Set the portal type to CMCC.	Bridge
cmcc-macauth	Set the portal type to CMCC and MAC authentication.	Bridge
auth-mac	When clients are authenticated and their MAC addresses are known, they are redirected to the external captive portal.	Tunnel
external-auth	Clients are directed to an external captive portal for authentication.	Bridge
external-macauth	Clients are directed to an external portal for MAC authentication.	Bridge

Configuring a FortiGate captive portal

The built-in FortiGate captive portal is simpler than an external portal. To configure a captive portal, you need to create an SSID, apply the SSID to the FortiAP, and create a policy from the SSID to the Internet.

The following shows a simple network topology for this recipe:

To configure a WiFi Captive Portal - GUI

1. Create a local user:
   1. Go to User & Authentication > User Definition, then click Create New.
   2. In the Users/Groups Creation Wizard, select Local User, then click Next.
   3. Enter the desired values in the Username and Password fields, then click Next.
   4. On the Contact Info tab, fill in any information as desired, then click Next. You do not need to configure any contact information for the user.
   5. On the Extra Info tab, set the User Account Status to Enabled.
   6. If the desired user group already exists, enable User Group, then select the desired user group.
   7. Click Submit.
2. Create a user group:
   1. Go to User & Authentication > User Definition, then click Create New.
   2. Enter the desired group name.
   3. For Type, select Firewall.
   4. For Members, click the + button. In the dropdown list, select the local user you created in step 1 and click OK.
   5. Click OK.
3. Create a captive portal SSID:
   1. Go to WiFi and Switch Controller > SSIDs, click Create New and select SSID.
   2. Enter the desired interface name. For Traffic mode, select Tunnel.
   3. In the Address > IP/Network Mask field, enter the IP address. DHCP Server is enabled by default. You can modify the DHCP IP address range manually.
   4. In the SSID field, enter the desired SSID name.
   5. For Security mode, select Captive Portal.

   6. Configure the following:

      Portal type	Configure a captive portal type: Authentication Disclaimer + Authentication Disclaimer Only Email Collection To enable Email Collection, go to System > Feature Visibility, and enable Email Collection, then select Email Collection for Portal Type. For information about each portal type, see Captive portal types.
      Authentication portal	Configure the location of the portal: Local - the portal is hosted on the FortiGate unit. External - enter FQDN or IP address of an external portal.
      User groups	Select permitted user groups or select Use Groups from Policies, which permits the groups specified in the security policy.
      Exempt sources	Select exempt lists whose members will not be subject to captive portal authentication.
      Exempt destinations/services	Select destinations and services lists whose members will not be subject to captive portal authentication.
      Redirect after Captive Portal	Select whether to have authenticated users navigate to their originally requested URL or be redirected to a specific URL.

   7. Click OK.
4. Select the SSID on a managed FortiAP. The following configuration is based on a example using a managed FortiAP-221E and a "FAP221E-default" profile that is applied to the FortiAP-221E. Do one of the following:
   1. Select the SSID by editing the FortiAP:
      1. Go to WiFi and Switch Controller > Managed FortiAPs. Select the FortiAP-221E and click Edit.
      2. Ensure that Managed AP Status is Connected.
      3. Under Wireless Settings, ensure that the configured FortiAP profile is the desired profile, in this case FAP221E-default. Click Edit entry.
      4. To broadcast the SSID from the 2.4 G radio, scroll to Radio 1 > SSIDs. Select Manual, then click + to select the captive portal SSID you created.
      5. To broadcast the SSID from the 5 G radio, scroll to Radio 2 > SSIDs. Select Manual, then click + to select the captive portal SSID you created.
      6. Click OK.
   2. Select the SSID by editing the FortiAP profile:
      1. Go to WiFi and Switch Controller > FortiAP Profiles. Select the FAP221E-default profile, then click Edit.
      2. To broadcast the SSID from the 2.4 G radio, scroll to Radio 1 > SSIDs. Select Manual, then click + to select the captive portal SSID you created.
      3. To broadcast the SSID from the 5 G radio, scroll to Radio 2 > SSIDs. Select Manual, then click + to select the captive portal SSID you created.
      4. Click OK.
5. Create the SSID-to-Internet firewall policy:
   1. Go to Policy & Objects > Firewall Policy, then click Create New.
   2. Enter the desired policy name.
   3. From the Incoming Interface dropdown list, select the source interface, such as wifi-vap.
   4. From the Outgoing Interface dropdown list, select the destination interface, such as wan1.
   5. In the Source and Destination fields, select all. In the Service field, select ALL. If desired, you can configure different values for these fields.
   6. Click OK.

To deploy captive portal SSID to FortiAP units - CLI

1. Create a local user:

   config user local

   edit "local"

   set type password

   set passwd ***

   next

   end

2. Create a user group:

   config user group

   edit "group-local"

   set member "local"

   next

   end

3. Create a captive portal SSID. You can assign the following portal-type:

   config wireless-controller vap
     edit "wifi-vap"
       set ssid "Fortinet-Captive"
       set security captive-portal
       set portal-type {auth | auth+disclaimer | disclaimer | email-collect}
       set selected-usergroups "group-local"
     next
   end

4. Configure an IP address and enable DHCP:

   config system interface

   edit "wifi-vap"

   set ip 10.10.80.1 255.255.255.0

   next

   end

   config system dhcp server

   edit 1

   set dns-service default

   set default-gateway 10.10.80.1

   set netmask 255.255.255.0

   set interface "wifi-vap"

   config ip-range

   edit 1

   set start-ip 10.10.80.2

   set end-ip 10.10.80.254

   next

   end

   set timezone-option default

   next

   end

5. Select the SSID on a managed FortiAP. The following configuration is based on a example using a managed FortiAP-221E and a "FAP221E-default" profile that is applied to the FortiAP-221E:

   config wireless-controller wtp

   edit "FP221E3X14000640"

   set admin enable

   set wtp-profile "FAP221E-default"

   next

   end

   config wireless-controller wtp-profile

   edit "FAP221E-default"

   config radio-1

   set vap-all manual

   set vaps "wifi-vap"

   end

   config radio-2

   set vap-all manual

   set vaps "wifi-vap"

   end

   next

   end

6. Create the SSID-to-Internet firewall policy:

   config firewall policy

   edit 1

   set name "WiFi to Internet"

   set srcintf "wifi-vap"

   set dstintf "wan1"

   set srcaddr "all"

   set dstaddr "all"

   set action accept

   set schedule "always"

   set service "ALL"

   set fsso disable

   set nat enable

   next

   end

Configuring an external captive portal

An external captive portal is a web page on a web server as opposed to the built-in captive portal on FortiGate. The essential part of the web portal page is a script that gathers the user's logon credentials and sends back to the FortiGate a specifically-formatted POST message. The portal page can also contain links to local information such as legal notices, terms of service and so on. Without authenticating, the user cannot access any other information. This is sometimes called a "walled garden".

On the captive portal page, the user submits credentials, which the script returns to the FortiGate at the URL https://<FGT_IP>:1000/fgtauth with data
magic=session_id&username=<username>&password=<password>.
(The magic value was provided in the initial FortiGate request to the web server.)

To ensure that credentials are communicated securely, enable the use of HTTPS for authentication:

config user setting

set auth-secure-http enable

end

To configure an external WiFi Captive Portal in tunnel mode - GUI

1. Go to WiFi and Switch Controller > SSIDs.
   If the SSID already exists, you can edit the SSID or you can edit the WiFi interface in Network > Interfaces.
2. Set the Traffic mode to Tunnel.
3. In Security Mode, select Captive Portal.
   

4. Select the Portal type you want.

5. In Authentication portal, select External and enter the FQDN or IP address of the external portal.

   Typically, this is the URL of a script. Do not include the protocol (http:// or https://) part of the URL.

6. Configure the other settings as needed.
7. When you are finished, select OK.

To configure an external WiFi Captive Portal in tunnel mode - CLI

config wireless-controller vap
  edit "wifi-vap"
    set ssid "Fortinet-Captive"
    set security captive-portal
    set external-web "example.com"
    set selected-usergroups "Guest-group"
    set schedule "always"
  next
end

To configure an auth-mac portal in tunnel mode - CLI

To support a MAC authentication portal (such as Cisco ISE authentication) in tunnel mode, you must set portal-type to auth-mac.

config wireless-controller vap
  edit wifi-cap
    set ssid "fortinet-guest"
    set security captive-portal
    set portal-type auth-mac
    set radius-mac-auth enable
    set radius-mac-auth-server "CISCO_ISE"
    set radius-mac-auth-usergroups "registered"
    set external-web "https://<ISE_Portal>:8443/portal/g?p=123456789"
  next
end

To configure an external WiFi Captive Portal in local bridge mode - CLI

config wireless-controller vap
  edit "cap"
    set ssid "fortinet-guest"
    set security captive-portal
    set external-web "example.com/portal"
    set radius-server "peap"
    set local-bridging enable
    set portal-type external-auth
  next
end

To configure an external-macauth portal in bridge mode - CLI

To support an external MAC authentication portal (such as Cisco ISE authentication) in bridge mode, you must set portal-type to external-macauth.

config wireless-controller vap
  edit wifi-cap
    set ssid "fortinet-guest"
    set security captive-portal
    set external-web "https://<ISE_Portal>:8443/portal/g?p=jN9z47goOJg75HpaXxV8WZPQgd"
    set radius-mac-auth enable
    set radius-mac-auth-server "ISE"
    set radius-mac-auth-usergroups "AuthorizedGuest"
    set local-bridging enable
    set portal-type external-macauth
    set schedule "always"
  next
end

Configuring MAC Bypass for captive portal

Captive portal security supports MAC-auth-bypass. If a client's MAC can be authenticated from local-user or a RADIUS server, then the client can bypass firewall authentication directly.

To configure MAC bypass for the captive portal SSID - CLI

config wireless-controller vap
  edit "cap"
    set ssid "fortinet-guest"
    set security captive-portal
    set mac-auth-bypass enable
    set selected-usergroups "group-radius"
  next
end