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The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Key Applications and Application Protocols            9  TCP/IP File and Message Transfer Applications and Protocols (FTP, TFTP, Electronic Mail, USENET, HTTP/WWW, Gopher)                 9  TCP/IP General File Transfer Protocols (FTP and TFTP)                      9  Trivial File Transfer Protocol (TFTP)

TFTP Options and Option Negotiation 1 2 3 4 5 TCP/IP Electronic Mail System: Concepts and Protocols (RFC 822, MIME, SMTP, POP3, IMAP)

Option Acknowledgment Messages

OACK messages are used to acknowledge receipt of TFTP options. They are structured as shown in Table 239 and Figure 300.

Table 239: TFTP Option Acknowledgment Message Format

Field Name	Size (bytes)	Description
Opcode	2	Operation Code: Specifies the TFTP message type. A value of 6 indicates an Option Acknowledgment message.
Options	Variable

TFTP Options and Option Negotiation 1 2 3 4 5 TCP/IP Electronic Mail System: Concepts and Protocols (RFC 822, MIME, SMTP, POP3, IMAP)