SpamAssassin - Use this program to "Unspam" your mailbox(es).
Truecaller - Find a person by a name or phone number worldwide for free using Truecaller.
MailScanner - MailScanner is a open source email security system design for Linux-based email gateways.
WhosCall - WhosCall is a reliable caller ID app whose popularity has led to its adoption by many users including international media. You can now manage the numbers calling you regardless of whether they are part of your contact list or not... read more.
Rspamd - Rspamd is an advanced spam filtering system that allows evaluation of messages by a number of rules...
CallApp - Free Caller ID & Call Blocker app that allows mobile users to block phone calls, identify calls, blacklist unwanted callers and much more.