Ways to fight spam in email?

Question

Email

Interested in ways to combat email spam?
How best to fight? to acquire special software for the server? Or on each machine to configure separately?
What is better to use? Are there any legal ways to combat spam?

Answer 1

There are four main ways.
1. Special software is installed on the server (for example, spamassasin, drWeb, Kaspersky anti-spam for Linux)
2. The server is configured to check the sender according to various rules (domain compliance check, check for black lists), etc. Usually, almost any special Software (the same spamassassin).
3. An anti-spam is installed on the client's machine (either a plug-in for the mail program, or a resident solution that intercepts pop3/smtp mail traffic).
Another option is that your postal service provider can do it for you. For example, antispam is built into google mail, many providers provide automatic spam checking of your mail for free or for a small fee.

Answer 2

postgrey is bullshit that should not be used in a professional environment. Only for extremely small offices, where the requirements for delivery speed and mail work are low.

Answer 3

For me personally, the first line of defense is postgrey Implemented on postfix, but there are similar solutions for exim and sendmail. I won't say for the rest.
For new, unknown addresses, it gives a technical error to the sender, which is actually a request to repeat the request later. No spammer will monitor their mail. And so they do not accept this request. Therefore, the letter is not resent. Those. it will never reach the recipient. And if this is an honest server, then within 5-15 minutes the letter will fall into the mailbox.
After 3 such letters, the user is whitelisted. And within half a year, letters from this addressee will come without delay. If the user has not written anything for more than half a year, he is considered new, and the procedure is repeated with a delay.