Captive Portal Explained: How It Works and What to Look For
A captive portal restricts network access until a user completes an access process.
Published by Protocol Explorer · Reviewed
How Captive Portal works
A device may discover portal information through network configuration and query a portal API. The user can then follow the venue’s access flow.
What to look for in an exchange
A portal login is separate from Wi-Fi association and IP configuration. HTTPS interception and application behaviour vary between networks.
Follow an example step by step
- Follow the device joining the local network and receiving IP configuration.
- Locate the advertised portal information or the access check used by the device.
- Follow the user-facing authorization flow and then check whether access restrictions change.
Common interpretation mistake
A captive portal is not the same thing as the Wi-Fi password or DHCP lease.
Key point to remember
Portal discovery and authentication can differ across operating systems and network deployments.
Explore the protocol
The Captive Portal overview is free without an account. Its full interactive lesson is included in Protocol Explorer Pro, a one-time $4.99 purchase; an account is required to buy Pro and restore the licence across devices.
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Specification
Read the primary specification for Captive Portal for the authoritative protocol details. The interactive scenario is a simplified teaching model, not a capture of your network.
Continue learning
How to read a packet · TCP · UDP · HTTPS