I have setup an Postfix based Email server as per the how to guidelines of this web site. But I am facing a security related problem regarding smtp port. anyone can connect to my stmp port (e.g telnet server-name 25). on that time unauthorized person send email to my domain user email without any authentication and all mail goes to spam box. Is there any way to stop email from telnet 25(unauthorized) port without affecting email sending & receiving capability. I am newbie so any help will be appropriated
What you describe above is no security problem, it is the normal way email works. If it would be required that users have to be authorized to send a email to a local mailbox, then nobody would be able you send you a email. Please dont mix this up with sending a email trough your server to a external email. Sending to a external email trogh your server requires authorization, but sending e amil to a local user can not require authorization. Thats not possible without disabling email receiving at alltogether.
