Google Apps email list spam prevention
Wednesday April 16, 2008 by Derek Young
At work we moved all our mail services to Google Apps. Maintaining our own mail server was a waste of time and resources. Our server spent most of its time processing spam, and went down at least once or twice. This downtime was more than enough to justify the price of the move.
You give up a lot of flexibility once you switch over to google’s servers though. You can’t run procmail, and the email list functionality is limited.
We quickly found out that some of our older email lists were spam targets, and mail that came to them flooded everyone’s spam folder. Google’s spam filtering is very good, but if you get hundreds of spams a day it’s next to impossible to search through them for false positives.
To keep spam sent to email lists away from the users I set up a layer of indirection. (In this example I’ll use “staff” as the email list name). I made one new mailbox account called “mail-router” and added staff as a nickname of this account. Then I created a new email list with an obscured name (xx-staff) that held the addresses of the employees that were meant to receive the mail. Now, in the mail-router account I created a filter to forward mail addressed to staff to xx-staff.
Gmail doesn’t forward spam, so all spam to the staff alias gets left in the mail-router account. The two hidden addresses (mail-router and xx-staff) can both be changed at any time in case they too are targeted with spam.
Because any feature of filters can be used you can also use filters to delete some mail or only forward mail if it matches a whitelist. To make a whitelist filter, use the Has the words field and enter an OR expression like this: from:gooduser@gooddomain.com OR from:gooduser2@otherdomain.com
The mail-router account costs an extra $50 per year (easily justified), but it can be used for any number of email lists. Hopefully Google will eventually introduce at least a simple whitelist/blacklist at the email list level.
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Thanks for the tip. I’ve been trying to figure out a good way of doing this for a while, and this is the closest I’ve seen to a workable solution.
— Evan B Dec 28, 02:46 PM #