110916     NOTAIL.MAC  Version: 8A, September 1991
 
Submitted by: Billy Youdelman, Consulting Electrical Engineer
 
Operating System: TSX-PLUS V6.31  Source Language: MACRO-11  Memory
Required: 1KB  Software Required: MACRO-11 for assembly, program must
be edited for site requirements then assembled and linked.  Keywords:
Emulators, Security, TSX-PLUS
 
Abstract: Tailgating is the name commonly given to what happens when a
modem data path is broken before the job using it has logged
off, and the next call is connected to that still active
session of the prior user.
 
TSX-PLUS was given improved modem control in V6.40, with
which tailgating incidents are easily prevented.  If you are
using TSX-PLUS V6.40 or later, then this program is not
necessary.  In either case, the information concerning
use of a logoff command file applies.
 
If you are using TSX-PLUS V6.31 or earlier, the TIMOUT value
which governs how long a job will be held active after the
data carrier has been lost, determines the time allowed for
a caller to first connect, type two returns and initialize
the line.  Thus setting TIMOUT small enough to prevent
tailgating means its not likely anyone will be able to
log on a phone line either.
 
This little program, running as a detached job, checks
designated lines every 0.5 second and kills any that may
still be logged on without DCD held true.
 
Changes and Improvements: Extended to work with Operating system
TSX-PLUS V6.0 through V6.31.
 
Restrictions: Operating system TSX-PLUS V6.0 through V6.31 is
required.
 
Media (Service Charge Code): One RX01 Diskette (KA)  Format: RT-11,
600' Magnetic Tape (MA)  Format: RT-11