POPFile is a

free Free may refer to: Concept * Freedom, having the ability to do something, without having to obey anyone/anything * Freethought, a position that beliefs should be formed only on the basis of logic, reason, and empiricism * Emancipate, to procur ...

open-source Open source is source code that is made freely available for possible modification and redistribution. Products include permission to use the source code, design documents, or content of the product. The open-source model is a decentralized sof ...

, cross-platform

mail filter Email filtering is the processing of email to organize it according to specified criteria. The term can apply to the intervention of human intelligence, but most often refers to the automatic processing of messages at an SMTP server, possibly appl ...

originally written in

Perl Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offici ...

John Graham-Cumming John Graham-Cumming is a British software engineer and writer best known for starting a successful petition to the Government of the United Kingdom asking for an apology for its persecution of Alan Turing. , he serves as Chief Technology Officer ...

and maintained by a team of volunteers. It uses a

naive Bayes classifier In statistics, naive Bayes classifiers are a family of simple "probabilistic classifiers" based on applying Bayes' theorem with strong (naive) independence assumptions between the features (see Bayes classifier). They are among the simplest Baye ...

to filter mail. This allows the filter to "learn" and classify mail according to the user's preferences. Typically it is used to filter

spam Spam may refer to: * Spam (food), a canned pork meat product * Spamming, unsolicited or undesired electronic messages ** Email spam, unsolicited, undesired, or illegal email messages ** Messaging spam, spam targeting users of instant messaging ( ...

mail. It can also be used to sort mail into other user defined "buckets" or categories - for example, the user may define a bucket into which work email is sorted. The program works in several different modes. In the most popular mode, it sets itself up as a

proxy Proxy may refer to: * Proxy or agent (law), a substitute authorized to act for another entity or a document which authorizes the agent so to act * Proxy (climate), a measured variable used to infer the value of a variable of interest in climate ...

between the email client and the

POP3 In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server. POP version 3 (POP3) is the version in common use, and along with IMAP the most common p ...

server. As mail is downloaded via POP3, the filter identifies and classifies mail and makes a user defined modification to the subject line, appending the name of the appropriate bucket. The user then sets up rules in the mail client to sort the mail based on the subject line modification. An

HTML The HyperText Markup Language or HTML is the standard markup language for documents designed to be displayed in a web browser. It can be assisted by technologies such as Cascading Style Sheets (CSS) and scripting languages such as JavaScri ...

based interface can be used to instruct POPFile, allowing users to correct errors in classifications and thus train the system to be sensitive to the user's specific requirements. As an alternative to the subject-line modification (or as a supplement to it), the system can also be configured to use custom mail headers instead. In another possible mode, POPFile can work as an

IMAP In computing, the Internet Message Access Protocol (IMAP) is an Internet standard protocol used by email clients to retrieve email messages from a mail server over a TCP/IP connection. IMAP is defined by . IMAP was designed with the goal of per ...

client that monitors an IMAP server for incoming mail and also for messages moved by the user. Incoming emails are categorized and then immediately moved to the folder corresponding to the categorization. To train POPFile in this mode, the user only needs to move the message to the correct folder, i.e. to the folder where POPFile should have moved the message.

External links

POPFile Official website
*{{SourceForge, popfile, POPFile
How to install POPFile on Mac OS X
2002 software Free email software Perl software Spam filtering