SSH Reference Manual

Configuring and Running SSH2
Configuration Overview
Administrators can specify configuration parameters of SSH2 processes through each of the following means:
• A configuration file
• PARAM commands
• Startup command line parameters
These different options enable system administrators to easily manage installations with multiple SSH2 processes,
including those running on multiple TCP/IP processes and ports as well as in different modes. For example, several
SSH2 processes that have identical SSH configurations can share the same configuration file, which streamlines
administration. On the other hand, process-unique parameters, such as the port to listen on, can be specified on the
command line.
On startup, SSH2 parses the sources of configuration parameter. A single parameter may be specified in multiple
sources, e.g. in the configuration file and on the startup command line. In this case, SSH2 will process parameters with
the following precedence (highest to lowest):
1. PARAM parameter
2. Parameter from configuration file 2 (CONFIG2)
3. Parameter from configuration file 1 (CONFIG)
4. Startup line parameter
This means that a parameter given in the configuration file will override the value given for the same parameter on the
startup line. Likewise, a parameter value given as a PARAM command will override any value specified in the
configuration file.
All SSH2 parameters can be specified in any of the configuration parameter sources, except in the following instances:
• The run mode of an SSH2 process is specified explicitly on the command line as the first startup line parameter.
This parameter defines the general functionality the SSH2 process will provide. (See the "Starting SSH2
"
section for details.)
• The configuration file to be used as a parameter source can only be specified as a PARAM or startup line
parameter, not in a configuration file.
It is important to note that parameter names are case insensitive, regardless of the manner in which way they are
specified.
HP NonStop SSH Reference Manual Configuring and Running SSH2 • 47