Programming the Perl DBI

Access configuration

The Net::Daemon, RPC::PlServer, and DBI::ProxyServer modules share a common configuration filesystem because of the ways that RPC::PlServer inherits from Net::Daemon and DBI::ProxyServer inherits from RPC::PlServer.^[68]

The configuration files for these modules are expressed as Perl scripts in which various options are set. The most useful options are those that allow you to specify access lists. Access lists allow you to control which machines may connect to the proxy server, and the mode that the network transport between these machines and the proxy server operates in.

For example, if you had a secure corporate LAN containing a database server and client PCs, you might say that the client PCs could connect to the central database via a proxy server without any authentication or encryption. That is, a PC connected to the LAN is trusted.

However, computers in employees’ houses that need access to the database are not trusted, as the data flowing across the phone line might be somehow intercepted by competitors. Therefore, the network transport between these machines and the central database server is encrypted.

A sample configuration file for the proxy server might look like:

{ facility => 'daemon', pidfile => '/var/dbiproxy/dbiproxy.pid', user => 'nobody', group => 'nobody', localport => '3333', mode => 'fork', # Access control clients => [ # Accept the local LAN ( 192.168.1.* ) { mask => '^192\.168\.1\.\d+$', accept => 1 }, # Accept our off-site machines ( ...