said by SHoTTa35 :How fast is your upload then? On that note, how big are these files are you scanning. Are you using WebMail or your own server or what?
In the first place, he is using an SMTP client. See this line from his headers:
Received: from SCE4009F ([69.141XXXXXX])
by omta01.westchester.pa.mail.comcast.net with comcast
id 4bQN1k00E0n8DgM3MbQXxS; Fri, 28 Sep 2012 11:24:32 +0000
The inclusion of a computer name ("SCE4009F") indicates the use of a Microsoft mail client; all others I have used "EHLO" with the computer's local IP Address.
In the second place, the email will not be moved to the next MTA in line until the submission server has received the complete message. So upload time is not a factor here.