FCSS_LED_AR-7.6 Exam Dumps : Fortinet NSE 6 - LAN Edge 7.6 Architect

Auto TX power control on FortiAP is an RF-optimization feature:

FortiGate (as wireless controller) continuously evaluatesRSSI of associated clientson each FortiAP radio.

The algorithm focuses on theweakest client(the one with the worst signal) and adjusts the AP’s transmit power so that this client’s signal level stays within a configured / target range.

This helps balance coverage and limit co-channel interference: APs don’t transmit at maximum power when clients are close, but will increase power when the weakest client signal drops too low.

Therefore the correct behavior description is:

✔C– AP power is adjusted based on the weakest associated client’s signal.

Why the others are wrong:

AandBtalk about matching nearby APs’ power or forcing everything to –70 dBm, which is not how FortiAP auto TX works.

Dincorrectly states the AP “evaluates its own transmission from the client perspective”; the AP can only infer client-side conditions from theclient’s RSSI at the AP, not the inverse.

From the exhibits:

SSID “Guest”

Security mode:Open

Captive Portal: Enabled, portal typeAuthentication → External

External portal URL: (FortiAuthenticator)

Exempt destinations/services:FortiAuthenticator and WindowsAD

Firewall policy

From theGuest interface/zonetoport1 (Internet)

Source user group:guest.portal(authenticated users)

The flow for anexternal captive portalis:

Client associates to theopen Guest SSID.

Client makes an HTTP(S) request.

FortiGate intercepts and redirects the client to theexternal portal.

Client must be able toreach FortiAuthenticator’s IP(and AD if the portal needs it)before authentication.

In this setup:

Theexempt destinationsetting tells the captive portal logicnot to require authenticationfor traffic going to FortiAuthenticator and WindowsAD.

However, there still must be a firewall policy that allows traffic from the Guest SSID subnet to those exempt destinations.

The existing firewall policy uses theguest.portal user groupas a source condition, which only matchesaftersuccessful portal authentication. Before login, the client has no user identity, so:

Traffic from the unauthenticated Guest client → FortiAuthenticator isnot matchedby that policy.

It hits theimplicit deny, so the browser never reaches the login page.

To fix this, the administrator must:

Create or modify a firewall policy thatallows traffic from the Guest SSID subnet/interface to FortiAuthenticator and WindowsAD without requiring user authentication.

That is exactly what optionDdescribes.

Why the others are wrong:

A. Change SSID security mode to WPA2-Enterprise– External captive portals are normally used withopenSSIDs; WPA2-Enterprise uses 802.1X, not captive portal.

B. Disable HTTPS redirection– Redirection is required so users are sent to the portal; disabling it doesn’t solve reachability.

C. Exclude FortiAuthenticator and Windows AD from filtering– They’re already listed asexempt destinationsin the SSID configuration; the missing piece is thefirewall policy, not the exemption.

In FortiLink NAC for LAN Edge:

When a device first connects, it is placed into theonboarding VLAN.

NAC policies then classify the device (by MAC, OS, user, EMS tag, etc.).

If a NAC policy matches, the device may be moved to anaccess VLANorquarantine VLAN.

Ifno NAC policy matches, the device simplystays in the onboarding VLAN.

FortiOS / LAN Edge documentation describes the onboarding VLAN as thedefault VLAN for unknown or unclassified devices, until NAC policy evaluation moves them elsewhere.