How to enable and configure sshd on SLES 12

This document (7018737) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 12

Situation

The yast module for configuring sshd (which was present in SLES 11) has not been included in SLES 12. To assist those who previously relied on that module, the information in the "Resolution" section below should be helpful:

Resolution

There are several topics to cover, including using other yast modules for some sshd related configuration, and using manual configuration methods. Not everything described here could be controlled through the discontinued yast2-sshd module, but is included as it is potentially useful.

1. Depending on the install method used, the sshd service is often enabled already, after installation. However, enabling or disabling sshd after the fact can be accomplished in these ways:

a. Within yast, sshd can be enabled/disabled (i.e. to set whether it launches at boot time) and started/stopped on the fly with the "Services Manager," which is found in the "System" section of yast.

b. At the command line, sshd can be enabled/disabled (i.e. to set whether it launches at boot time) with:

systemctl enable sshd

systemctl disable sshd

c. At the command line, sshd can be started or stopped on the fly with:

systemctl start sshd

systemctl stop sshd

2. The configuration items which were handled within the discontinued yast2-sshd module are part of the file /etc/ssh/sshd_config. Those items (and many others which were not shown in yast) can be set there. Some informational comments are present in the file, but more information can be found in he manual (man) page for sshd_config (command: man sshd_config).

3. For configuration that applies to how the sshd binary itself is launched: These options are the ones described in the man page for sshd, and are less commonly changed than the options described in the man page for sshd_config.

a. In yast, these can be set under the System section in "/etc/sysconfig editor." There, SSH can be found under Network --> Remote Access.

b. Alternatively, these options can be set directly in the file /etc/sysconfig/ssh.

Cause

The yast2-sshd module was distributed in SLES 11. It only handled a portion of what could be set in /etc/ssh/sshd_config, so it was not always useful for various configuration needs. This and other concerns caused debate about it's inclusion in the product. A decision was reached to remove it before SLES 12 shipped.

Disclaimer

This Support Knowledgebase provides a valuable tool for SUSE customers and parties interested in our products and solutions to acquire information, ideas and learn from one another. Materials are provided for informational, personal or non-commercial use within your organization and are presented "AS IS" WITHOUT WARRANTY OF ANY KIND.