1 Introduction

The NT LAN Manager (NTLM) Authentication: Post Office Protocol–Version 3 (POP3) Extension specifies the use of NTLM authentication (see [MS-NLMP]) by the Post Office Protocol 3 (POP3) to facilitate client authentication to a Windows POP3 server. POP3 specifies a protocol for the inquiry and retrieval of electronic mail. For a detailed definition of POP3, see [RFC1939].

Note For the purposes of this document, the NT LAN Manager (NTLM) Authentication: Post Office Protocol–Version 3 (POP3) Extension is referred to in subsequent sections as the "NTLM POP3 Extension".

The NTLM POP3 Extension uses the POP3 AUTH command (see [RFC1734]) to negotiate NTLM authentication and to send authentication data.

Sections 1.5, 1.8, 1.9, 2, and 3 of this specification are normative. All other sections and examples in this specification are informative.