1.4 Relationship to Other Protocols
The IMAP4 NTLM extension uses the IMAP4 AUTHENTICATE extension mechanism, described in [RFC1731], and is an embedded protocol. Unlike standalone application protocols, such as Telnet or HTTP, packets for this extension are embedded in IMAP4 commands and server responses.
The IMAP4 NTLM extension specifies only the sequence in which a client and a server are required to exchange NTLM messages to successfully authenticate the client to the server. It does not specify how the client obtains NTLM messages from the local NTLM software or how the server processes NTLM messages. The client and server implementations depend on the availability of an implementation of NTLM, as described in [MS-NLMP], to obtain and process NTLM messages and on the availability of base64 encoding and decoding mechanisms, as described in [RFC4648], to encode and decode the NTLM messages that are embedded in IMAP4 packets.
For conceptual background information and overviews of the relationships and interactions between this and other protocols, see [MS-OXPROTO].