thc-pptp-bruter [options] <remote host IP>
  -v        Verbose output / Debug output
  -W        Disable windows hack [default: enabled]
  -u <user> User [default: administrator]
  -w <file>  Wordlist file [default: stdin]
  -p < >    PPTP port [default: 1723]
  -n < >    Number of parallel tries [default: 5]
  -l < >    Limit to n passwords / sec [default: 100]
This Windows hack reuses the link control protocol (LCP) connection 
with the same caller ID. This gets around Microsoft's anti-bruteforcing 
protection. It's enabled by default.