SSH, The Secure Shell: The Definitive Guide, 2nd Edition

Tectia Extensions to Server Configuration Files

In Chapter 5, we described the server configuration files in detail, including OpenSSH’s sshd_config and Tectia’s sshd2_config. Tectia provides several levels of configuration not found in OpenSSH, called metaconfiguration and subconfiguration, and also some unusual rules for quoted values. We now cover them in detail.

11.6.1 Metaconfiguration

Tectia recognizes specially structured comments at the beginning of configuration files. These lines determine the syntax rules for the rest of the file, and are therefore called metaconfiguration information.

Configuration files distributed with Tectia all start with lines of the form:

    ## SSH CONFIGURATION FILE FORMAT VERSION 1.1
    ## REGEX-SYNTAX egrep
    ## end of metaconfig
    ## (leave above lines intact!)

The first line specifies the syntax version number, and defines the start of the metaconfiguration information. Increasing syntax version numbers allow the syntax rules to be extended, possibly in incompatible ways. As long as older configuration files explicitly specify their syntax versions, they can still be correctly understood by newer versions of the Tectia server.

The default syntax version (used if there is no metaconfiguration information) is 1.0. This refers to the “traditional” syntax rules understood by Tectia versions before Version 3.0.0 (when the metaconfiguration information syntax was introduced). The latest syntax version at press time is 1.1.

Syntax rules are further refined by ...