Shrinkster and Spam Firewalls

I made an interesting discovery today. As I was drafting the announcement email that was sent to all of the Day of .NET attendees, I sent a copy to a few of my email addresses, including my work address. To my surprise, our spam firewall (Baraccuda) blocked it!

I did several tests to try to identify why, and finally I found the culprit: Shrinkster URLs.

You see, we were sending a really long link into Windows Live Local (mapping web site). I thought that it looked bad, so I used Shrinkster to shorten it. The resulting URL was:

http://shrinkster.com/er6

Wouldn't you know it? Baraccuda flags this as "Intent" (whatever that means), and denies it by default.

So, unless Barracuda changes their global policy, you will not be able to send an email containing Shrinkster links to someone behind one of their Spam firewalls.