Network Working Group J. Postel
Request for Comments: 885
TELNET END OF RECORD OPTION
This RFC specifies a standard for the ARPA Internet community. Hosts on
the ARPA Internet that need to mark record boundaries within Telnet
protocol data are expected to adopt and implement this standard.
1. Command Name and Code
2. Command Meanings
IAC WILL END-OF-RECORD
The sender of this command requests permission to begin
transmission of the Telnet END-OF-RECORD (EOR) code when
transmitting data characters, or the sender of this command
confirms it will now begin transmission of EORs with transmitted
IAC WON'T END-OF-RECORD
The sender of this command demands to stop transmitting, or to
refuses to begin transmitting, the EOR code when transmitting data
IAC DO END-OF-RECORD
The sender of this command requests that the sender of data start
transmitting the EOR code when transmitting data, or the sender of
this command confirms that the sender of data is expected to
IAC DON'T END-OF-RECORD
The sender of this command demands that the receiver of the
command stop or not start transmitting EORs when transmitting
END-OF-RECORD is not transmitted.
4. Motivation for the Option
Many interactive systems use one (or more) of the normal data
characters to indicate the end of an effective unit of data (i.e., a
record), for example, carriage-return (or line-feed, or escape).
Some systems, however, have some special means of indicating the end
of an effective data unit, for example, a special key. This Telnet
option provides a means of communicating the end of data unit in a
5. Description of the Option
When the END-OF-RECORD option is in effect on the connection between
a sender of data and the receiver of the data, the sender transmits
It seems probable that the parties to the Telnet connection will
transmit EORs in both directions of the Telnet connection if EORs are
used at all; however, the use of EORs must be negotiated
independently for each direction.
When the END-OF-RECORD option is not in effect, the IAC EOR command
should be treated as a NOP if received, although IAC EOR should not
normally be sent in this mode.
6. Implementation Considerations
As the EOR code indicates the end of an effective data unit, Telnet
should attempt to send the data up to and including the EOR code
together to promote communication efficiency.
The end of record is indicated by the IAC EOR 2-octet sequence. The
code for EOR is 239 (decimal).