Chapter 3. Operating NetView FTP V2.2.1 MVS - IBM

Appendix A. Data Integrity and Data Security
Data Integrity
NetView FTP V2.2.1 MVS allows effective use of the security functions of VSAM
and System Authorization Facility (SAF) for MVS-controlled processors. In addition,
it provides you with pre-transfer, post-transfer, and post-conversation user exits that
permit you to implement an installation-defined security scheme. For further information
on the pre-transfer, post-transfer, and post-conversation user exits, refer to
the NetView FTP Customization guide.
Note: The pre-transfer, post-transfer, and post-conversation user exits are not
available for OSI transfers.
Between the creation of a file-transfer request and its execution there is a time gap.
As long as the file transfer has not been started, NetView FTP V2.2.1 MVS does
not lock the sending or receiving data sets to ensure that the data is not modified.
This can leave data exposed, unless you apply precautions against modifying the
data sets before the transfer begins.
You can use the not-before and not-after parameters in the file transfer request to
mark a time interval within which NetView FTP V2.2.1 MVS can transfer a data set.
You must ensure that the data sets are not changed within this interval.
Checking for the Correct Data Set with Job Allocation
If you use job allocation to identify the sending or receiving data set, you must code
a DD statement in the startup job or procedure of the server accessing the data
set.
To ensure that the correct data set has been found, you can specify the name of
the sending or receiving data set in the file-transfer request. NetView FTP V2.2.1
MVS checks the names of the data set in the DD statement against the data-set
name in the file-transfer request. If it finds a mismatch, it stops the file transfer.
Checking the Consistency of the Parameters in a Request
Before NetView FTP V2.2.1 MVS transfers any data, it checks that parameter
values in the file-transfer request are consistent and valid. Because an inconsistency
suggests a possible integrity exposure, NetView FTP V2.2.1 MVS rejects the
request before any data is transferred.
Checking the Completeness of a File Transfer
Unless you use a user-written file handler to access data, NetView FTP V2.2.1
MVS maintains a count of sent and received records during a file transfer. At the
end of the file transfer the two counts are compared. If a discrepancy is found a
message is issued and a return and a reason code is set up. These codes tell the
request originator that the file transfer was not successful.
Even if a file transfer fails, the receiving data set exists and jobs that process the
received file will process incomplete data.
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