Email Problem

Cannot work out why a person at my work is receiving email not directly addressed

to him. He is receiving over 100 per day.
He is receiving emails addressed to,
eg
user-account@ourdomainname.com.au
mail-boxes@ourdomainname.com.au
all-users@ourdomainname.com.au
Plus other titles recipient, user_info.
He should only receive email addressed as hisname@oudomainname.com.au
No one else in the Company has this problem.

If I send one of the above it is immediately returned to me.

For security I have changed the domain name to ourdomainname.
Any help would be appreciated.

Examples
This mail was generated automatically.
More info about --HOTMAIL-- under: http://www.hotmail.com

-------

Occured_Errors:

63.2.251.53_does_not_like_recipient.

% 375: Giving_up_on_63.2.251.53.

% 394: mailbox_unavailable

% 485: Remote_host_said:_Requested_action_not_taken

% 310: This_account_has_been_disabled_[#300].

End

-------

The corrected mail is attached. (The attachement is usually a virus.)

Auto_Mail.System: [hotmail]

user-account@ourdomainname.com.au
Microsoft Mail Internet Headers Version 2.0
Received: from fehsva.com ([138.130.73.167]) by servername.ourdomainname.local with Microsoft SMTPSVC(6.0.3790.0);
Wed, 1 Dec 2004 09:49:14 +1100
From: Error_Mail@hotmail.com
To: user-account@ourdomainname.com.au
Date: Tue, 30 Nov 2004 22:23:22 GMT
Subject: Mail delivery_failed <SMTP:3771>
Importance: Normal
X-Priority: 3 (Normal)
X-MSMail-Priority: Normal
Message-ID: <e4eede56fbad8978@hotmail.com>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="====7645248.063622c74ed1ff97"
Content-Transfer-Encoding: 7bit
Return-Path: Error_Mail@hotmail.com
X-OriginalArrivalTime: 30 Nov 2004 22:49:15.0109 (UTC) FILETIME=[D12D4950:01C4D72E]
--====7645248.063622c74ed1ff97
--====7645248.063622c74ed1ff97
Content-Type: application/octet-stream; name=hotmail_8808.zip
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="hotmail_8808.zip"

--====7645248.063622c74ed1ff97--
-------------------------------------------------------------
Another header example
--------------------------------------------------------
Microsoft Mail Internet Headers Version 2.0
Received: from swiftel.com.au ([202.154.92.30]) by servername.ourdomainname.local with Microsoft SMTPSVC(6.0.3790.0);
Wed, 1 Dec 2004 14:37:02 +1100
Received: (qmail 18578 invoked from network); 1 Dec 2004 03:29:23 -0000
Received: from unknown (HELO yommlohd.com) (138.130.73.167)
by babbage.swiftel.com.au with SMTP; 1 Dec 2004 03:29:23 -0000
From: user_info@hotmail.com
To: All_Users@ourdomainname.com.au
Date: Wed, 01 Dec 2004 01:46:51 GMT
Subject: FwD: Your mail password
Importance: Normal
X-Mailer: E-SMTP V9.74
X-Priority: 3 (Normal)
X-MSMail-Priority: Normal
Message-ID: <83abaa23fd9bd10ce9d0@hotmail.com>
MIME-Version: 1.0
Content-Type: multipart/mixed; boundary="9efebd59e515.030"
Content-Transfer-Encoding: 7bit
Return-Path: user_info@hotmail.com
X-OriginalArrivalTime: 01 Dec 2004 03:37:02.0843 (UTC) FILETIME=[058C64B0:01C4D757]
--9efebd59e515.030
--9efebd59e515.030
Content-Type: application/octet-stream; name=hotmail_992.zip
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="hotmail_992.zip"

--9efebd59e515.030--

Has an alias been setup on the mail server, that redirects or forwards all mail to his account?

No I cannot find any alias for this account. My best guess at this stage

is a virus being sent from another location.

Not sure if this will help or not. But, a letter was recieved to my family from earthlink. Let me quote what they said:


MESSAGE QUARANTINED

Virus Detected: W32.Sober.I@mm!enc

Message Details:
From: Error_Mail@hotmail.com
To: some.name.we.do.not.know@earthlink.net
Subject: Re: illegal signs in your mail
Date: Sat, 18 Dec 2004 22:05:59 GMT


EarthLink Virus Blocker has quarantined a message sent to
you because it contains a virus that cannot be removed or
disabled.

Quarantined messages are automatically deleted three days
after they are received.

Wasn't sent to our address. It was stopped by earthlnk before it was sent to our e-mail. Seems that the name is not to our account.
We also do not know of an account with this name. Notice the "Virus Dectected" I did a search and it seems to be some sort of worm.

Hope this helps.