K9 Spam Filter


K9 is a single-EXE spam filter, much easier to set up than the Perl scrip Pop3Proxy. Just run the EXE (preferably by adding a link to Windows's StartUp folder or the Run section of the Registry), and configure your e-mail client to connect to K9 running on TCP 9999, using a custom login name so K9 knows how to connect to a remote POP3 server.


  1. Download and run K9
  2. Open a DOS box, run "netstat -an", and make sure an application is listening on TCP 9999
  3. Launch your e-mail client, and make the following changes:
    1. POP3 Server =, POP3 port = 9999, Login name = pop.acme.com/110/jdoe (where jdoe is your login name given to you by your ISP)
    2. Create a  new folder to receive e-mail marked by K9 as SPAM, and create a new filter so your e-mail knows how to discriminate good e-mail from SPAM. by default, as shown in its Configuration tab, K9 marks SPAM-looking e-mails by adding "[spam]" at the end of the subject line. Personally, I changed this to using "X-Text-Classification: spam" instead. If you make any change to K9, you might need to restart K9 for changes to take effect
  4. Run your e-mail client, send yourself some SPAM-looking e-mail, check that K9 marks it as SPAM, and that your e-mail client does move this e-mail to its SPAM folder. You might need to launch the K9 app, and mark some SPAM as.. SPAM :-) Looks like K9 requires some learning before being operational.


Eudora 5.x doesn't let me use a port other than 110 for POP3 access

Edit eudora.ini in Eudora's directory, and change the line that says POPPort from its default 110 to 9999. Next, edit the properties of the Dominant account, with Login name = pop.isp.com/110/jdoe, and Incoming server =