TITLE:  TF2253 - TCP RST flag ignored
README FOR: TF2253

PRODUCT AND VERSION:

UnixWare 2.03

Abstract
--------

Sequence Number is not reset properly

Symptom
--------

Network laser printer buffer fills up in the process of receiving job
from remote 2.01 host. Printer is powered off to clear paper jam
for a few seconds during which UnixWare host repeatedly retries the
connection with ACK segments. When printer is switched back on it responds to
these ACKs by repeatedly sending back RST segments, but UnixWare host
fails to close connection and continues instead to ACK with the same
Sequence number and Acknowledgement number that it was using prior to the
RST segments being sent. Scheduler has to be stopped and restarted to
resume printing, but ACKs and RSTs continue on the old sequence
numbers until UnixWare system shut down.


SOLUTION SPECIFICS
------------------


Apply the tf2253 file.
 
 
Installation Instructions:
 
DATATYPE: datastream
 
1.  Download the tf2253.Z and the tf2253.txt files to the /tmp directory
    on your machine.
 
2.  Read the release notes contained in this file.           
 
3.  Now become root, uncompress the file and add the package to your 
    system using the following commands:
 
      $ su
      # uncompress /tmp/tf2253.Z
      # pkgadd -d /tmp/tf2253 


General Description.
-------------------

Sequence number is reset if we're sending a SYN (or SYN/ACK). 
The fix relies on the second SYN/ACK having the same sequence
number as the original and in consequence it will (assuming
the first SYN/ACK didn't get lost) be dropped by the client.


New Features.
------------

None

Software Notes and Recommendations.
----------------------------------

This PTF can be installed on UnixWare 2.03 

Testing of the modified software contained in this package has
been conducted only to the extent necessary to confirm that it
resolves the problem(s) stated above ("Symptom").  Such testing
consists of recreating the problem conditions (typically in a
SCO test laboratory) and verifying that the problem no longer
occurs.  No other testing of this software has been done.

Hardware Notes and Recommendations.
----------------------------------

This PTF is targeted for the i386, i486 and Pentium CPU's.