Email server address is clear for all

[said123]

I have noticed that whenever you send a message to unknown email address an error message will come back to your email address showing clearly the mail server address, I think this is not acceptable by all resellers.

The error message sample is as follow :
==========================================
Hi. This is the qmail-send program at mail2.hsphere.cc.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

<SAAAAAA@HOTMAIL.COM>:
63.4.11.222 does not like recipient.
Remote host said: 550 Requested action not taken: mailbox unavailable
Giving up on 63.4.11.222.

--- Below this line is a copy of the message.
=========================================
What do you think ?

It's the difference between buying shared hosting and buying a dedicated server. You can't hide everything from everyone.

Mail servers don't work without names, and a given machine has only one true hostname. We'd have to rewrite at least the MTA and probably stamp on several RFCs to work around this. Whatever we do, in the end there's always a PTR or ARIN to give us away.