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Wi Fi Security
Having to maintain the security of a wireless network is something that’s probably new to most users, and it can often be frustrating due to all the new information you have to assimilate.
How Wi-Fi hotspots force you to log in.
It's an everyday scenario: you go to a hotel or Wi-Fi hotspot and find a wireless or wired connection, but instead of getting your homepage when you bring up your browser, you get a custom page from the service provider asking you to pay for the service. You've hit a captive portal, and it's how the service provider makes sure that they get paid for what they are offering.
The technology is relatively simple because you are, by definition, using their network. They configure their systems to accept your initial network traffic (in this case, your request for Web content from your homepage's server) but instead of passing that request along, they redirect you to their sign-in page. This redirection can be done in a number of ways, but the basic functionality is built into the http standard (the status codes in the 300-range describe the various options). Any non-web traffic, such as SMTP for email, or FTP, is typically blocked using a firewall of some type, but may be caught and redirected by a particularly sophisticated captive portal.
Once you
sign in
and pay up, the captive portal stops interfering with your traffic,
and reverts to the usual 'pass through' mode. The next time you try
to connect, it checks your identity (usually by looking at your machine's
relevant MAC address) and silently let you through if you are still
in the time-window of service. Otherwise, it's back to square one.
So,
to summarize, the captive portal provider needs: a redirection mechanism
for Web traffic, a traffic-blocking mechanism of some sort (firewall,
802.1x, etc) to constrain you, a sign-in facility, a payments gateway
of some sort, and some form of identity repository for keeping track
of who is a paid-up known customer and who is not.
None of these
components are particularly obscure or difficult to find, but if you
are looking to build a captive portal you probably shouldn't try to
reinvent the wheel. You can find complete packaged hardware-and-software
solutions from the usual suspects (Cisco, Juniper, etc), as well as
smaller-scale software solutions from multiple vendors. If you want
to use free and open-source software, you'll easily be able to find
many solutions on-line.
About the author, judy sim is a freelance
fulltime writer.
For more information of this article please visit
www.easy-home-business.blogspot.com
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