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>if it fails for any reason, they bring up a modal panel showing the captive portal AFAIK, technically, there's no standard address for a captive portal's loca

by ferongr 12y ago

>if it fails for any reason, they bring up a modal panel showing the captive portal AFAIK, technically, there's no standard address for a captive portal's location so iOS probably tries to navigate to a website. The router then poisons the DNS response and the captive portal loads. Android devices do the same thing to my knowledge. My Samsung pops up a notification that when tapped opens the browser and tries to navigate to Google. If a login happens before the user opens the notification (for example, by an app running a background service like the Fonera app) the notification is cleared automatically.

0x0 12y ago
Actually, most captive portals don't poison the cache (because that would break the web site you tried to load), but answers on port 80 for any and all IP addresses.
- ferongr 12y ago
  To my knowledge you can use a TTL of 0 and then you have no problems.
  - 0x0 12y ago
    Wouldn't that cause problems with (a) browsers that cache dns for a little while anyways, and (b) clients arriving on the captive net but already holding a long-lived cached proper dns result?