Odd way to fill your mailbox

On a site of mine I get an email every time an invalid url is requested. The purpose of that is mainly to find broken links. Sometimes a misconfigured crawler may spam me with a hundred mails, but they're pretty easy to delete and it doesn't happen frequently.

Tonight however, from 21.08 to 21.53, I received more than 3.500 such, all from the same ip. It would probably have been more if i didn't block that ip at 21.53, as I luckily was at the computer. The requested url:s were all directories and pages that exist on the site, but combined in odd ways, primarily stacking directories in long chains that doesn't exist.

As I don't have access to the firewalls of my hosting company I had to figure out a way to block the weirdo myself. My solution was to just terminate requests from that host in my asp.net page like this (but the real ip instead of the x:es):

  protected void Page_Load(object sender, EventArgs e)
  {
      if (Request.UserHostAddress == "x.x.x.x") {
          Response.End();
          return;
      }
      ...
  }