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MF66548 - OSP-COMM-TCPIP-OTHER-UNPRED AFTER TCP WINDOWUPDATE SEND OF H

PTF Cover Letter


PTF ( Program Temporary Fixes ) Cover letter


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Abstract

OSP-COMM-TCPIP-OTHER-UNPRED AFTER TCP WINDOWUPDATE SEND OF H


Pre/Co-Requisite PTF / Fix List

REQ  LICENSED           PTF/FIX  LEVEL

TYPE PROGRAM  RELEASE   NUMBER   MIN/MAX  OPTION
---- -------- --------- -------  -------  ------
TR   5770999  V7R2M0    MF99109   00/00    0000



NOTICE:
-------
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APAR Error Description / Circumvention

-------------------------------------------------
The VNIC client device driver (CCIN 2BD4) is incorrectly padding
short frames residing in an external buffer during transmit.
One symptom of this problem was a transmit overwriting an
external buffer with zeroes causing a subsequent transmit of a
TCP window update to be malformed.

CORRECTION FOR APAR 'MA47902' :
-------------------------------
The VNIC client device driver on IBM i will pad Ethernet frames
which are shorter than 60 bytes with zeroes while transmitting.
In some cases, this padding could overwrite data intended to be
used by subsequent transmits which can lead to incorrect
information being sent.  The device driver will be changed to
copy the data into it's own buffer if it needs to pad to prevent
potentially overwriting network stack buffers.

CIRCUMVENTION FOR APAR 'MA47902' :
----------------------------------
None.


Activation Instructions

None.




Special Instructions

None.


Default Instructions

THIS PTF CAN BE APPLIED IMMEDIATE OR DELAYED.



Supersedes

PTF/FIX NO(S).  APAR TITLE LINE
--------------  ------------------------------------------------------------
     NONE

Summary Information

System..............................i
Models..............................
Release.............................V7R2M0
Licensed Program...............5770999
APAR Fixed..........................View details for APAR MA47902
Superseded by:......................
Recompile...........................N
Library.............................QSYS
MRI Feature ........................NONE
Cum Level...........................C0114720


IBM i Support

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Document Information

Modified date:
16 May 2020