anthony@NMS.HLS.COM (Anthony Chung) (11/26/90)
Most of TELNET implementations have implemented TELNET echo option correctly.
But, interfaces between TELNET and applications which use TELNET are not
implemented correctly.
Echo may come from applications even TELNET WON't ECHO. For examples:
1. A word processor software which interfces with TELNET layer may
not know about result of ECHO negotiation.
2. A host may not know anything about TELNET negotiations when
TELNET code resides in a intelligent Ethernet controller.
3. A host does not even know about TELNET when it connnects
to a TCP/IP terminal server over RS232.
These problems exist for other options too, such as Binary option.
I think all these problems are local implementation issue.
I also have found problem which some TELNET implementations do not follow
TELNET End-Of-Line convention. I also found SUN OS(at least version 4.0.3)
still expects Supress Go Ahead negotiation to get out line mode. "Host
Requirements" RFC specifies that server TELNET SHOULD NOT support sending
GA commands. Sometimes I wonder that I should follow RFC or not.