Custom 'not responding' screen?

Hey,

Basically I’ve seen on some servers that the server crashes, they have a custom-made notification and also a reconnect button.
How would I make something like that? ( How would I know when the server is not responding/crashes so I can popup the notification and the button )

Cheers.

http://forum.facepunch.com/showthread.php?t=989733&p=41762485&viewfull=1#post41762485

Thanks.