<li><a href="http://perl.apache.org/">mod_perl</a> (if compiling your own mod_perl, make sure you set the <a href="http://perl.apache.org/guide/install.html#EVERYTHING">EVERYTHING</a>=1 compile-time option)
<li><a href="http://www.openssh.com/">SSH</a> (<a href="http://www.openssh.com//">OpenSSH</a> is recommended. SSH Communications Security <a href="http://www.ssh.com/products/ssh/download.cfm">commercial SSH version 3</a> has been reported incompatible with Freeside.)
<li><a href="http://rsync.samba.org/">rsync</a>
+ <li>Optional, enables typeset invoices: teTeX and Ghostscript (included with most distributions).
<li>A <b>transactional</b> database engine <a href="http://search.cpan.org/search?mode=module&query=DBD%3A%3A">supported</a> by Perl's <a href="http://dbi.perl.org">DBI</a>.
<ul>
<li><a href="http://www.postgresql.org/">PostgreSQL</a> is recommended (v7or later).