Postfix configure anti spam with blacklist FOLLOWING DIRECTIVES TO /ETC/POSTFIX/MAIN.CF FILE: => DISABLE_VRFY_COMMAND = YES : Disable the SMTP VRFY command. This stops some techniques used to harvest email addresses. => SMTPD_DELAY_REJECT = Y...

It is becoming more common that ISPs are blocking PORT 25 (SMTP port) forcing you to use their SMTP server. To see if you are blocked: 1. Click Start Button (Windows Desktop) 2. Click Run 3. Enter telnet" 4. Enter "open mail.domain.com 25" If yo...

The standard port used for SMTP connections is 25. One of the most common reasons for not being able to send messages is that your Internet service provider blocks this port. This is why using an alternative SMTP port [1] is highly recommended. Here...