Locked out because of too many unsuccessful attempts

I've started using n.nu with a group of students (more than 100) and now during sessions in the computer laboratory they are getting the message that they are shut out of their sites due to too many unsuccessful login attempts from the school's IP address. This makes n.nu useless from an academic perspective. Is there any way around this problem. Help appreciated.

Hi Sean,

Nice that you are using N.nu as a tool in your school.

The blocking of IP for a number of hours for repeated password attempt is a security measure which is necessary. However, an email is sent to the owner of the website with a link. By clicking this link the block is lifted.

But I have now cleared all blocking of all IPs. So you can login now again. I hope you don't get this problem again.