Spampig DnsblCheck takes the IP address of a mail server and looks it up in common blacklists and whitelists. The program tests against the major block lists from Spamhaus, SORBS, Spamcop, Barracuda, UCEProtect, and others. In addition to blacklists, it also checks against IP address and domain name whitelists and even checks PTR record integrity. The program returns results quickly, typically in less than a few seconds. If you don't get results quickly, it indicates you may have DNS problems and knowing this can also be useful. This application can be useful to spam fighters and email users who are struggling to find out why their messages are being blocked.
jsoup is a Java library for working with real-world HTML. It can parse HTML from a URL, file, or string. It can find and extract data, using DOM traversal or CSS selectors. The HTML elements, attributes, and text can be manipulated. It can clean user-submitted content against a safe white-list. jsoup is designed to deal with all varieties of HTML found in the wild, from pristine and validating to invalid tag-soup; jsoup will create a sensible parse tree.
Jaro Mail is an integrated suite of interoperable tools for GNU/Linux and Apple/OS X to manage email communication in a private way, without relying on online services (in fact, encouraging users to store email locally). It mainly features a system for mailinglist filtering, address-book integrated whitelisting, strong encryption and anonymous remailing, long-term email storage and archiving with functions for fast search and usage statistics. To accomplish all that, it makes use of solid Unix tools like Mutt, Fetchmail, Mairix, Msmtp, GnuPG, Abook, ELinks, and Mixmaster.