What Mail Server Do The Fortune 100 Companies Use?

By Daniel Miessler on August 18th, 2006: Tagged as Business | Email | Internet | Sysadmin

Ever wonder what mail servers the top U.S. companies run? I found myself wondering what the top universities used a while back, and I just recently got curious as to what the Fortune 100 companies used as well. The results were quite interesting; it’s always fun to see what some of these admins put in their mail banners:

220 plgmler2.imr.gm.com ESMTP Sendmail GM Secure; Thu, 17 Aug 2006 23:23:21 -0500
220 mail11.disney.com Postfix EGGS and Butter 
220 IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted
220 Medco - Ready 220 mailgate2.safeway.com ESMTP ***** SMTP Ready *****
220 mail1.cat.com ESMTP Microsoft Exchange Internet Mail Service 5.5.2657.72) ready
220 Northrop Grumman Corporation Ready
220 mms01bas.mms.us.syntegra.com (IntraStore TurboSendmail) ESMTP Service ready
220 [12.43.78.22] ESMTP
220 wamu.com Proxy Server 220 fdsmail01.fds.com Microsoft ESMTP MAIL Service, Version:
5.0.2195.6713 ready at Fri, 18 Aug 2006 00:31:58 -0400

Quite a few of the banners warn anyone reading not to use the service for spam, although I have to wonder whether or not a spammer has ever changed their behavior due to a warning like this.

We also get to see some personality in the way the servers say goodbye (SMTP 221):

221 Bye
221 Until later [69.214.242.13]
221 Catch you later

Anyway, here are the complete results as well as the stuff I used to run the test:

Input

The Script The Company File

Output

The Complete Banners The Exit Messages

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** Note: There’s a fine line between being curious about interesting service banners and portscanning. If you don’t know what that difference is then you probably shouldn’t be doing this at home. :)

Viewing 4 Comments

tyler 2 years ago 1 point
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Very interesting Daniel. I just found your blog, and really enjoy it. We cover many of the same topics. I added you to my blogroll too so I won't forget you. :)

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http://www.longren.org/

Chris 2 years ago 1 point
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Heh. Who can resist customizing their Postfix banner. I'd forgotten mine...still like it.

220 mail.icantfocus.com ESMTP Postfix (Trained Shaved Monkeys)

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Steve 2 years ago 1 point
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Looking at banners doesn't answer your original question.

These responses:
220 ******00*******************************************0****0****0 **********************200**22****20 *0*00
Are typical of PIX. There's many others in the results file that don't identify a particular mail server.

Aside from that, to find out what they actually use, you should have sent an email that would bounce (or generate a reply of any sort), then examine the headers. Or, use a search engine to find postings to some mailing list from someone at the company in question and do the same thing.

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Daniel Miessler 2 years ago 1 point
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Agreed, Steve, but I wasn't trying to *really* enumerate what they were using; the test was really more along the lines of "Fortune 100 SMTP Banners", but I didn't have the presence of mind to name it that at the time. :)

Thanks for the note...

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