Redirect all traffic on my network to a welcome page [closed]

When someone connects to my network and tries to browse, I would like to redirected to a welcome page. I know there are some commercial solutions for hotspots out there, what I am looking for is just redirecting. Ideally, I could set this network rule from the command line, not through the network admin GUI. Can you guide me with some keyworks or tutorials I should follow to do this?

EDIT: The network is a WLAN like in a hotel. Ideally was looking for a router-independent solution, but advice on a Netgear Aircard, for instance, would be enough.

Solution 1:

Technical solution/explanation:

From the network point of view, you need to configure two elements:

• webserver (Apache, Ngix,..)
• iptables to forward all port 80 packets transparently to the new webserver IP port 80

You will have to create a web page but this will be complicate because you probably want to forward the user to the original page after the introduction. This could be done using a server side language like PHP, to proxy the connections to the original page after the introduction has been shown.

Easy solution:

Note that technical solution above is quite complicate to achieve if you don't have knowledge on the different technologies required (i.e. iptables, apache, php). I'd then rather look for a product integrating already these elements.

For example, a costumer router software like http://dd-wrt.com or also http://openwrt.org already provides this functionality. They also provide the WLAN configuration you need.