Dovetailed Technologies

1. Introduction

z/OS OpenSSH and IBM Ported Tools OpenSSH (for z/OS versions older than V2R2) include a port of the popular OpenSSH tools. These tools provide for secure remote login and program execution (ssh) and file transfer (sftp and scp). The sftp and sftp-server commands implement a file transfer program that is similar to ftp, but use ssh for their underlying secure transport. The sftp specification [1] accounts only for binary transfers. The IBM z/OS sftp client has been enhanced to support ASCII-EBCDIC conversion. Dataset support is not provided.

The Co:Z Co-Processing Toolkit for z/OS includes Co:Z SFTP - a port of the OpenSSH (v7.6p1) sftp-server subsystem and sftp command (renamed as cozsftp). Extensive enhancements have been made to support z/OS facilities such as z/OSS datasets and spool files. z/OS OpenSSH or IBM Ported Tools OpenSSH, as applicable based on the z/OS version, is required since Co:Z does not provide the base ssh and sshd components.

1.1 Features

  • Co:Z is compatible with most existing sftp products (see the section called “Remote Client Requirements”).

  • Transfer datasets via the get and put commands

  • Navigate z/OS catalogs via the cd command.

  • List dataset information and PDS directories via the ls command.

  • Records SMF 119 records if user has BPX.SMF SAF authorization.

  • Support for IBM FTP compatible user exits. A guide to setting up and using these exits can be found here:

  • Supports direct access to datasets which can be opened in sequential, record mode by the fopen() C-library routine. This includes:

    • MVS sequential datasets (QSAM, BSAM, VSAM)

    • PDS and PDSE members

    • SYSOUT datasets, including the MVS internal reader

  • Supports JES2 and JES3 job submission, status and spool file transfer on z/OS 1.9 or later. Future releases of Co:Z SFTP will also support cancel and purge facilities.

  • Supports text or binary conversion via flexible line-termination rules:

    • Cr, Lf/Newline, CrLf, Cr and/or Lf, RDW, none

  • Supports flexible record padding / overflow rules

  • Can specify dataset dynamic allocation (BPXWDYN) keywords

  • Can specify name patterns to automatically associate file transfer options to POSIX files and datasets

1.2 Supported Environments

z/OS Requirements

Running Co:Z SFTP with z/OS userids that have superuser authority or UID=0 OMVS segments is not recommended.

Remote Client Requirements

  • Co:Z SFTP is compatible with a wide variety of operating systems, including Windows, *IX variants, z/OS...

  • Products supporting the SSH File Transfer Protocol, such as:

    • OpenSSH

    • puTTy psftp

    • winSCP

    • gFTP

    • Many commercial implementations.

    Note: Not all products support all of the Co:Z SFTP extensions. Refer to Client Compatibility for additional information.

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