Echo Negotiation in Telnet

[jdd at allegra.UUCP]

"Telnet" in 4.1c has great difficulty talking to 3Com UNET uvtp servers;
when it turns local echoing off it never turns it back on.  The fix is to
add the following case in dooption() in /usr/src/ucb/netser/telnet/telnet.c:

	case TELOPT_ECHO:
		(void) mode(2);
		fmt = will;
		hisopts[option] = 0;
		break;

Whoever wrote telnet.c just forgot to handle this one, but telnetd never
sends one of these so it probably didn't come up during testing.

Cheers,
John ("Network Demon") DeTreville
Bell Labs, Murray Hill