Pseudo ping, using telnet sequence TIMING(0x06).
#ping 0 to force reset upon network timeout.
Note: MudOS and most Unix hosts support it. Some MudOS needs to send a "\n" after that.
#ping2 not work with some Mud that does not implement some basic telnet response,
as an alternate, use system pseudo variable $_msec and some self-made actions to
do similar work.