What it means
A captive portal is the page that appears when a Wi-Fi operator requires terms, a room number or another access step before allowing internet use. It says something about access to that network, not whether the Wi-Fi name is genuine or the rest of your browsing is secure.
A real-world example
A café has a real portal, but a nearby attacker advertises a similar Wi-Fi name and opens a convincing-looking page. Checking the exact network name with staff reduces that risk; entering a bank password into the portal would be unjustified.
What to do
Use the venue's confirmed network, give only information necessary for access and then visit important services through their correct HTTPS addresses. Forget the network afterward if appropriate.
The distinction that matters
A password-protected hotspot is not automatically safer than an open one with HTTPS websites. FTC's public Wi-Fi advice explains the role of encryption; Microsoft notes captive portals can still trigger unsafe-network warnings.
FTC public Wi-Fi guidance Microsoft's portal explanation
