Sending mail from your Postfix how to avoid spam?

Question

Java

Good afternoon, the problem is that if the java that collects the letter and sends it via postfix is ​​located on the same server as postfix, then the letter does NOT go to the spam folder. If you run a java program from another machine (relative to the postfix server), then the letter goes to spam. Question: It is necessary to make it possible to fully send a letter from another server. How is this problem solved?

Answer 1

How to bypass spam is a very general question,
no less general answer:
First of all, you should have properly configured (listed in order of importance): PTR
(rDNS)
SPF
DKIM
DMARC
[email protected] [email protected] [email protected] even without localhost these senders are bad (for their presence you can add spamscore) Thirdly,
don't spam =)