from HPING2-HOWTO.TXT:

0001: What is hping?

  Hping is a software to do TCP/IP stack auditing, to uncover firewall
  policy, to scan TCP port in a lot of different modes, to transfer
  files accross a firewall and many other stuff. Using hping you are
  able to do a lot of not security-regarding stuff. For example you
  can test networks performance, check if a host is up, check if TOS
  is handled et cetera.

-d.