IPN verification response problem.

[webteron]

Hi!

I'm using https://www.paypal.com/cgi-bin/webscr. Does it makes any different rather than https://ipnpb.paypal.com/cgi-bin/webscr?

The response of these URL can only be either VERIFIED or INVALID? Can it be something else?
Sometimes I get some strange characters as response. What could be the problem?

Although it's from live environment I hope I selected the correct Category/Board.