Ever wonder what mail servers people run? I found myself wondering what the top universities used, so I wrote a lame little script to go and query the top 50 schools from this list, find out their mail servers, and then netcat to them to see what they respond with.

The results were interesting. I was specifically wondering how the war between Sendmail and Postfix was going. As expected, Sendmail is still winning, but Postfix seems to be holding its own.

So out of 36 responses I got 7 with Postfix in the banner. If we take that highly unscientific sample and call it legit, we’re looking at roughly 20% of top-50 universities using Postfix. Not bad.

Aside from the MTA war, though, it was just interesting to see what these guys were putting in their banners. Check out the Princeton one, for example — they have some sort of secret message encoded with MD5 in theirs. And MIT points out that they don’t want any collect or third party calls. Nice.

Anyway, here are the results and the tool I used. Be sure to check out the raw output as well; there are quite a few interesting tidbits in there.:

Files

[ The Results ]
[ The Raw Results ]
[ The Script I Used ]
[ The List of Universities I Used ]

I just finished getting Mail.app to recognize two seperate SSL certs from my server — one for imap.dmiessler.com, and another for smtp.dmiessler.com. This was less than trivial (mostly due to my own stupidity).

What this means is that I can finally use real domain names in my certificates (self-signed) for two separate hostnames while avoiding the annoying prompts that OS X likes to throw when it senses tomfoolery.

Here are the steps:

• Create your Postfix certificates the way Weitse wants you to, using your SMTP hostname.
• Import both the CA cert and your actual Postfix certificate into OS X.
• For IMAP, edit your imapd.cnf file to reflect your IMAP hostname, etc.
• Run mkimapdcert.
• Import that certificate into OS X.

Now when you open Mail.app you should not get prompted to accept any certificates. The trick is that you need to import the CA’s cert on the Postfix side or it won’t work. But with courier this is not required. It has something to do with the format of the certificates being different.

It’s on my list of things to research, but for now I’m just happy I got it working exactly as I want it.

I just finished moving my email infrastructure to the new server (Gentoo + Deathgod Box of Doom). I had to wrangle quite a bit with SMTP-AUTH this time, and found very little help out there that didn’t have to do with using MySQL for the authentication piece. For me (and probably many others), that’s just overkill.

So after figuring out how to do it I decided to do a writeup on it. I would very much like to save others from having to go through the same thing I did. Plus, when I inevitably forget a step someday I’ll have this to refer to:

How To Get Postfix To Use SMTP-AUTH WITHOUT Using MySQL