Mainframe connection options

Required role: system administrator

Determining your connection protocol

There are several ways for Zowe client applications to connect to the mainframe, each offering its own advantages. Deciding which type of connection to use — Zowe Remote SSH, z/OSMF, or FTP — ultimately depends on what works best with your mainframe environment. Consult your system administrator to determine the best path for you.

Zowe Remote SSH (introduced in Zowe v3.6)

SSH (Secure Shell) is a cryptographic network protocol that offers a quick way to get started with Zowe client applications.

Use SSH to connect to the mainframe without having to configure a service such as z/OSMF. If you have a z/OS user account, for example, and SSH is enabled for that system, then you can easily access your z/OS UNIX resources over SSH.

SSH supports basic authentication and public/private key authentication.

note

The SSH daemon (sshd) that is used on the mainframe server to accept client connections has to be enabled on that LPAR/system. If you do not have sshd running on one of the LPARs, you cannot connect to that system using SSH.

To use SSH with Zowe Explorer (v3.6 and above), see the Zowe Remote SSH documentation. To keep track of updates to functionality as ZRS develops, see the Zowe Remote SSH functionality documentation.

z/OSMF

Part of IBM z/OS, z/OSMF (IBM z/OS Management Facility) is a web browser-based graphical interface and REST API framework that offers a way to communicate with the mainframe.

To use z/OSMF, a system administrator must configure and enable the service on the mainframe. When configured, z/OSMF is a common way for users to access mainframe resources.

z/OSMF is accessible over a REST API and can be registered as a service with API Mediation Layer. z/OSMF supports basic authentication and certificate authentication. When using API ML, you can authenticate using a token.

To use z/OSMF, see the IBM z/OS Management Facility documentation.

z/OS FTP

File Transfer Protocol (FTP) is a basic protocol that follows a standard set of rules to upload, download, or transfer data between your local computer and the mainframe. FTP sends data only over plain text in either ASCII or binary transfer modes, resulting in limitations that can expose sensitive information and restrict the type of data that can be transferred.

FTP is solely for accessing or modifying resources. FTP does not support console, TSO, or system operations.

You can authenticate only with basic authentication when using FTP.

It is not recommended to use FTP unless you are using File Transfer Protocol Secure (FTPS), an FTP extension that uses Transport Layer Security (TLS) encryption to protect your data. Note that FTPS is different from SFTP (SSH File Transfer Protocol), which is a way to encrypt FTP traffic over SSH.

To use FTP with Zowe CLI, see the IBM z/OS FTP Plug-in for Zowe CLI documentation. To use FTP with Zowe Explorer, see the Zowe Explorer for IBM z/OS FTP documentation. To learn about FTPS, see the IBM documentation on File Transfer Protocol.

Comparing Zowe Remote SSH, z/OSMF, z/OS FTP

Three common ways to reach mainframe resources (data sets, USS files, jobs, console) from a client tool.

	Zowe Remote SSH	z/OSMF REST API	z/OS FTP
Data transfer security	Encrypted by default	Encrypted by default	Plain text unless FTPS is added
Resources supported	Data sets, USS files, jobs, console, TSO	Data sets, USS files, jobs, console, TSO	Data sets, USS files, jobs
Interactive performance	Fast — one persistent connection	Moderate — stateless request per call	Slow — reconnects per transfer
Large file transfer	Good, some encoding overhead	Workable, but has known issues with very large files	Strong, built for bulk transfer
Setup effort	Low — deploy binaries over existing SSH access	Higher — needs z/OSMF configured and started	Minimal — usually already running
Client tooling	Zowe CLI, Zowe Explorer, Node.js SDK	Zowe CLI, Zowe Explorer, any REST client	Any FTP client or language
Best for	Low-latency interactive tooling, no extra mainframe middleware	Standardized REST automation, sites already running z/OSMF	Scripted bulk transfer, legacy integration

note

VSAM record access is not natively supported by any of the three. Console and TSO commands are not available over FTP.