Well, chirpy is right with what he says on that link. But he is referring to the default address. Let's make sure we're differentiating these things correctly:
Default address != ANY filter
I think this is a misunderstanding that most end-users don't get. And it may be a misunderstanding that cPanel is not understanding. Everyone thinks fail is what you should do all the time, but they don't understand the context of where it is being used.
Consider an SMTP transaction, when sending to a non-existant email account:
Code:
# telnet mail.yourmailserver.com 25
Trying XX.XX.XX.XX...
Connected to mail.yourmailserver.com
Escape character is '^]'.
220-mail.yourmailserver.com ESMTP Exim 4.85 #2 Fri, 05 Feb 2016 12:44:12 -0500
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.
EHLO servername
250-mail.yourmailserver.com Hello servername
250-SIZE 52428800
250-8BITMIME
250-PIPELINING
250-AUTH PLAIN LOGIN
250-STARTTLS
250 HELP
mail from: <[email protected]>
250 OK
rcpt to: <[email protected]>
550 No Address Here
DATA
503-All RCPT commands were rejected with this error:
503-No Address Here
503 Valid RCPT command must precede DATA
This is correct. This is the
DEFAULT ADDRESS being set to fail.
But an email that has a filter:
Code:
# telnet mail.yourmailserver.com 25
Trying XX.XX.XX.XX...
Connected to mail.yourmailserver.com.
Escape character is '^]'.
220-mail.yourmailserver.com ESMTP Exim 4.85 #2 Fri, 05 Feb 2016 12:48:29 -0500
220-We do not authorize the use of this system to transport unsolicited,
220 and/or bulk e-mail.
EHLO servername
250-mail.yourmailserver.com Hello servername
250-SIZE 52428800
250-8BITMIME
250-PIPELINING
250-AUTH PLAIN LOGIN
250-STARTTLS
250 HELP
mail from: <[email protected]>
250 OK
rcpt to: <[email protected]>
250 Accepted
DATA
354 Enter message, ending with "." on a line by itself
From: <[email protected]>
To: <[email protected]>
Subject: Test Message
I'm the part of the message that's going to hit the filter.
.
250 OK id=1aRkUo-0004Su-O4
quit
221 mail.yourmailserver.com closing connection
Connection closed by foreign host.
In this example, this message was accepted (note
id=1aRkUo-0004Su-O4). But because
[email protected] has a filter set to filter messages that contain "I'm the part of the message that's going to hit the filter." and fail them, then
yourmailserver.com is going to try to send that fail message to
[email protected]. But it's not going to work, because
[email protected] isn't a real email address that is accepting messages. This is bounceback hell.