How can we show up a warning to a user after connecting to WiFi?

[basurajagrawal]

I am planning to allow up a guests to access my wireless network (802.1x with dedicated username and password say).

How do i show them up a warning that your access to internet can be tracked for security reasons? typically its a one-time warning which pops up when the system gets connected to WiFi.


Addon Info:
Using a Cisco Linksys EA4500 router, and a free radius server.

 

[RadiclDreamer]

Most of these types of captive portals are on enterprise level gear, Im not sure if this is a doable thing with what you have, I am very interested to see if someone else has a solution though.

 

[jumpncrash]

dd-wrt has some options, but I don't know if your router supports it