SSL/TLS Strong Encryption: Compatibility

This page covers backwards compatibility between mod_ssl and otherSSL solutions. mod_ssl is not the only SSL solution for Apache; fouradditional products are (or were) also available: Ben Laurie's freelyavailableApache-SSL (fromwhere mod_ssl were originally derived in 1998), Red Hat's commercialSecure Web Server (which was based on mod_ssl), Covalent's commercialRaven SSL Module (also based onmod_ssl) and finally C2Net's (now Red Hat's) commercial productStronghold (basedon a different evolution branch, named Sioux up to Stronghold 2.x, andbased on mod_ssl since Stronghold 3.x).

mod_ssl mostly provides a superset of the functionality of all the othersolutions, so it's simple to migrate from one of the older modules tomod_ssl. The configuration directives and environment variable namesused by the older SSL solutions vary from those used in mod_ssl;mapping tables are included here to give the equivalents used by mod_ssl.

• Configuration Directives
• Environment Variables
• Custom Log Functions

See also

• Comments

Configuration Directives

The mapping between configuration directives used by Apache-SSL1.x and mod_ssl 2.0.x is given inTable1. The mapping from Sioux 1.x and Stronghold 2.x is only partialbecause of special functionality in these interfaces which mod_ssldoesn't provide.

Table 1: Configuration Directive Mapping

Environment Variables

The mapping between environment variable names used by the olderSSL solutions and the names used by mod_ssl is given inTable 2.

Table 2: Environment Variable Derivation

Custom Log Functions

When mod_ssl is enabled, additional functions exist for theCustom Log Format ofmod_log_config as documented in the ReferenceChapter. Beside the ``%{varname}x''eXtension format function which can be used to expand any variables providedby any module, an additional Cryptography``%{name}c'' cryptography format functionexists for backward compatibility. The currently implemented function callsare listed inTable 3.

Table 3: Custom Log Cryptography Function