RFC 933 (rfc933) - Page 2 of 4
Output marking Telnet option
Alternative Format: Original Text Document
RFC 933 January 1985 Output Marking Telnet Option IAC SB OUTMRK ACK IAC SE The sender acknowledges the data and agrees to use it to perform output marking (see below). IAC SB OUTMRK NAK IAC SE The sender objects to using the data to perform output marking (see below). 3. Default WON'T OUTMRK Output marking information will not be exchanged. DON'T OUTMRK Output marking information will not be exchanged. 4. Motivation for the Option The security architecture of some military systems identifies a security level with each Telnet connection. There is a corresponding need to display a security banner on visual display devices. (Reference: Department of Defense Trusted Computer System Evaluation Criteria, Section 3.1.1.3.2.3, Labeling Human-Readable Output.) The output marking is currently done by transmitting the banner as data within each screen of data. It would be more efficient to transmit the data once with instructions and have User-Telnet maintain the banner automatically without any additional Server-Telnet action. This frees Server-Telnet from needing to know the output device page size. Under this proposal Server-Telnet would send an option sequence with the command, a control flag, and the banner to be used. While current systems use the top of the screen, it is conceivable other systems would want to put the banner at the bottom or perhaps even the side of the screen. This is the reason for the control flag. 5. Description of the Option Either side of the session can initiate the option; however, normally it will be the server side that initiates the request to perform output marking. Either the Server-Telnet sends "WILL OUTMRK" or the User-Telnet sends a "DO OUTMRK". The party receiving the initial Silverman
