If the environment variable DBI_AUTOPROXY is defined (and the driver in $data_source is not ``Proxy'') then the connect request will automatically be changed to:

  $ENV{DBI_AUTOPROXY};dsn=$data_source
DBI_AUTOPROXY is typically set as ``dbi:Proxy:hostname=...;port=...''. If $ENV{DBI_AUTOPROXY} doesn't begin with 'dbi:' then ``dbi:Proxy:'' will be prepended to it first. See the DBD::Proxy documentation for more details.