Simply go to any forum that is powered by invision board and add this to the end of there forum URL

?ipscheck=true&key=ipscheck$1@@

For instance here is lavasofts…

http://www.lavasoftsupport.com/?ipscheck=true&key=ipscheck$1@@

If it retuns a valid customer number and order number instead of blanks
and zeros then its a valid board. Now this will only work on peeps who
have not changed the key from ipscheck$1@@ to something else.

ເຜື່ອໄດ້ໃຊ້ 😉