Apache SpamAssassin is an extensible email filter that is used to identify spam. Once identified, the mail can then be optionally tagged as spam for later filtering. It provides a command line tool to perform filtering, a client-server system to filter large volumes of mail, and Mail::SpamAssassin, a set of Perl modules allowing Apache SpamAssassin to be used in a wide variety of email systems.
DiaNa is a Perl framework designed to process a huge amount of data, performing from very easy to very complex tasks in a very efficient, spreadsheet-like, batch fashion. DiaNa also features an interactive Perl/Tk GUI, layered on the top of several batch shell-scripts. The DiaNa syntax is a very small and orthogonal superset of the underlying Perl syntax, which allows, for example, comfortable addressing of file tokens and profitable use of file formats throughout the data processing.
The HTML::Defaultify Perl module is designed to allow CGI programmers to present forms with some fields filled in, which is handy for letting users correct bad input, show records to be edited, and much more. The main function, defaultify(), takes any block of HTML and a hash of field names and values, and returns the HTML with the form fields set to those values. Value lists for multiple same-named fields are supported, as are pages with multiple forms. Several different input formats are supported for compatibility with existing tools.
Linguaphile is a simple command line language translator. It is open source, platform independent, and programmed in Perl. Linguaphile currently supports the following languages: Afrikaans, Alawa, Albanian, Arrernte, Basque, Belarusian, Bulgarian, Catalan, Croatian, Czech, Danish, Dutch, English, Esperanto, Estonian, Finnish, French, Galician, German, Greek, Hawaiian, Hungarian, Icelandic, Indonesian, Interlingua, Irish, Italian, Kala Lagaw Ya, Korean, Kriol, Latvian, Lithuanian, Malay, Maltese, Maori, Norwegian, Pitjantjatjara, Polish, Portuguese, Romanian, Russian, Samoan, Serbian, Slovak, Slovenian, Spanish, Swahili, Swedish, Thai, Tok Pisin, Turkish, Ukrainian, Warlpiri, and Welsh. The Spanish to English translation is the most useful at this stage.
PMilter implements Sendmail's "milter" mail filtering protocol in Perl, allowing scripts direct access to the SMTP transaction in progress, rather than filtering later. It can function as a drop-in replacement for Sendmail::Milter, though PMilter does not require threads or the "libmilter" API to be available.
libsrs2 is the next generation SRS library. SPF verifies that the Sender address of an email message matches (according to some policy) the client IP address that submitted it. When a message is forwarded, the sender address must be rewritten to comply with SPF policy. The Sender Rewriting Scheme, or SRS, provides a standard for this rewriting that is not vulnerable to attacks by spammers, is easy to parse by common mail filters, and handles multiple hops neatly and safely.
qpsmtpd is a flexible smtpd daemon written in Perl. Apart from the core SMTP features, all functionality is implemented in small "extension plugins" using the easy-to-use object oriented plugin API. qpsmtpd was originally written as a drop-in qmail-smtpd replacement, but now it also includes an smtp forward and a postfix "backend".