11. The Internet Engineering Task Force ( " IETF " ) is responsible for this design. 12. The Internet Engineering Task Force publishes Best Current Practice documents in a numbered document series. 13. In due course Kerberos was made an open, extensible standard of the Internet Engineering Task Force . 14. PPTP has not been proposed nor ratified as a standard by the Internet Engineering Task Force . 15. The XFF HTTP request header was introduced by the Internet Engineering Task Force ( IETF ). 16. Many Internet engineers are worried, saying VeriSign is proceeding before the Internet Engineering Task Force approves standards. 17. A suite of SIP-related Internet Engineering Task Force ( IETF ) rules define behavior for such applications. 18. In January 2013, the Internet Engineering Task Force published a number of threat models for OAuth 2.0. 19. Kristol's idea is under review by the Internet Engineering Task Force , which sets standards for Internet software. 20. The Internet Engineering Task Force published the original specifications in RFC 882 and RFC 883 in November 1983.