How to stop "Join [network name]" pop ups for proxy wifi

Using OS 10.10.1

I'm connecting to a wifi network that has most of the internet blocked. The problem is, every 10 minutes or so a pop-up window will appear saying "Join [network name]", but the content of the pop-up is blocked by the network.

I assume it's some kind of login window, but the internet works without any login.

At the bottom of the pop-up is a site address of what it's trying to access. The websites seem to cycle between these:

• www.ibook.info


• www.airport.us


• http://ift.tt/1qjaNBo

And the actual address url looks something like:

http://ift.tt/1HJebBR

Is there a way to stop the pop-ups? or disable whatever is trying to access those sites?