E-Mail relay or break in?

[sysadmin () SASSPRODUCTIONS COM (Seth Georgion)]

Mid-day today, while logged in to my exchange 5.5 server at the console, I recieved an E-Mail from myself to myself. 
Technically it was a "Just Testing" kind of message from my Administrator account to my SysAdmin account. Of course I 
never sent it and after further investigation I discovered that the E-Mail was most certainly sent by telnet and then 
subsequently, about a minute later, recieved by my copy of Outlook 2000. Before anyone gives me anything about "Did I 
read my logs?" The answer is yes and they indicate that the connection originated to and from my machine. Let me 
preface the main question with the statement that this server has been up for 30 hours and due to other crises around 
here has not had mail-relaying disabled yet. My first assumption was that someone was mail-relaying me and just forging 
the info but because I have a near paranoid interest in logging Exchange stuff I was suprised to see that it went 
beyond a simple forged E-Mail. My question is simply "Is this someone creating a telnet session and forging an E-Mail 
and tricking out Exchange or is this someone who has compromised my server and is now trying to gain control of some 
E-Mail?"

Here's relevent logs.
Note: GATE is the name of the server, the ip address, 192.168.1.254 is internatl because we use NAT pools.

Here are two Event Logs for it

SMTP connection to Exchange from the Exchange server itself

Date:   2/8/00  Event ID:       2000
Time:   3:14:42 PM      Source: MSExchangeIMC
User:   N/A     Type:None
Computer: GATE  Category: SMTP Interface Events

Description:
A new TCP?IP SMTP connectio has been recieved from host GATE
Logfile: L00000000.LOG

This is the Message transfer and description file.

Date: Above                     Event ID:       2002
Time:   3:14:43 PM              Source: Above
User: N/A                       Type: Information
CComputer: GATE         Category: Message Transfer

Description
A Message from <administrator () sassproductions com> in temporary folder \imcdata\in\1QHMKPJ7 was recieved from GATE 
with 1 local recipients.

Here's the E-Mail as stored in imcdata.

â   ImCr        0

:Gr¿
        GATE GATE <Administrator () sassproductions com>   c=US;a= ;p=SASS Productions;l=GATE00020820141QHMKPJ7    
   
   O   
       ASS         8  8          <sysadmin () sassproductions com>  known  EwLsReceived: from GATE 
([192.168.1.254]) by gate.sassproductions with SMTP (Microsoft Exchange Internet Mail Service Version 5.5.2650.21)
        id 1QHMKPJ7; Tue, 8 Feb 2000 15:14:43 -0500
From: Administrator () sassproductions com
To: sysadmin () sassproductions com
Subject: This is a test mail

This is a test message...did I get it

And here is the log of what the person typed in word for word.

2/8/00 3:14:42 PM : A connection was accepted from GATE.
2/8/00 3:14:42 PM : <<< IO: |HELO 
|
2/8/00 3:14:42 PM : <<< HELO 
2/8/00 3:14:43 PM : >>> 250 OK

2/8/00 3:14:43 PM : <<< IO: |MAIL FROM:<Administrator () sassproductions com>
|
2/8/00 3:14:43 PM : <<< MAIL FROM:<Administrator () sassproductions com>
2/8/00 3:14:43 PM : >>> 250 OK - mail from <Administrator () sassproductions com>

2/8/00 3:14:43 PM : <<< IO: |RCPT TO:<sysadmin () sassproductions com>
|
2/8/00 3:14:43 PM : <<< RCPT TO:<sysadmin () sassproductions com>
2/8/00 3:14:43 PM : >>> 250 OK - Recipient <sysadmin () sassproductions com>

2/8/00 3:14:43 PM : <<< IO: |DATA
|
2/8/00 3:14:43 PM : <<< DATA
2/8/00 3:14:43 PM : >>> 354 Send data.  End with CRLF.CRLF

2/8/00 3:14:43 PM : <<< IO: |From: Administrator () sassproductions com
To: sysadmin () sassproductions com
Subject: This is a test mail

This is a test message...did I get it
.
|
2/8/00 3:14:43 PM : >>> 250 OK

2/8/00 3:14:43 PM : <<< IO: |QUIT
|
2/8/00 3:14:43 PM : <<< QUIT
2/8/00 3:14:43 PM : >>> 221 closing connection

So what is it? Locally originated or jst a very clever disguise attempt? Well not just an attempt... ;)