Sometimes if you use the "free" WiFi service of an open internet wireless connection, you get redirected to their webpage instead of your homepage when first opening your internet browser or trying to go to a webpage.

 

How do they accomplish that?

If you control the router, you control what it gives to anything connected through it.

I noticed that 'borrowed' Wifi scenario happens when I use Windows; but not on Linux.

Since it comes with their own modem device which act as a client, it may be possible that the client device by default request for a service to display their homepage after the connection has been established. I use a wireless internet connection and even though I changed the settings (of the modem device) of the options tab and made the URL- as a default page, it continues to display their homepage at start up irrespective of what URL you specify there.

Edited December 11, 201114 yr by immortal

The most common way is messing with DNS,

perhaps your linux is set to always use a certain dns server?

I've spent a lot of time in hotels this year and I haven't found one yet that doesn't redirect me (either for 802.1x authentication or just to advertise their homepage).

 

The "HTTP Redirect" is normally done by the wireless lan controller, or a Radius/Tacas server performing authentication IF used.

 

It really depends on the technology, but a simple example would be this.

 

1. User connects to wireless and opens web browser with homepage set for "www.google.com"

2. DNS request is sent / received

3. TCP handshake completes

4. Client sends a HTTP GET to google server

5. Wireless lan controller sees the "HTTP GET" intercepts the packet and reply's back to the client with its configured redirect page.

 

 

Using Linux wouldn't stop a "http redirect", not sure what you mean Externet?

I know much less than you about the subject, but I report the fact; I experience no redirectioning with Linux. (Ubuntu 10.10 flavor)

Is this just at one place, or multiple hotspots that normally redirect?

 

Some wireless spots are configured to redirect you to a web-based authentication page, and until you are authenticated you would be unable to access the internet. This could be a curse if redirection truly doesn't work.

 

I would be more suspicious of the web browser vs the OS. I assume you would be using Firefox or ice weasel with Ubuntu, is Firefox what you use with your windows machine as well?