Memo to novice postmaster

I would like to give some general advice to email administrators. I hope it will be useful for beginners, and an experienced reminder will be able to check the status of their systems for normal, smooth email circulation, as well as for better spam filtering with a minimum of false positives.

1. Be sure to set the reverse zone for your mail server (ptr record). It is not so difficult to do. In most cases, it is enough to write to your ISP. Then either he will register in his dns, or he will delegate your zone to you (in-addr.arpa).
2. Try to keep up to date the correspondence of the PTR record with A, which is indicated by the MX record.
3. Use fqdn in the HELO / EHLO greeting
4. Check that you are not using openrbl.org in RBL lists. This service has long been closed and blocks all recipients.
5. Enable the ability to work on a secure tls connection. Let even with the self-signed certificate, but which has the correct common name , which coincides with your PTR record. Use both SMTP over SSL and submission services.
6. Do not prohibit delivery status notification in your postal users, they greatly simplify the solution of problems that arise.

These are very short tips, but based on their experience, no more than 30% of mail servers in the CIS can withstand them.

PS If it is required, I will write how to implement it with reference to postfix.