PLEASE READ ALL CORRESPONDENCES IN THIS THREAD BEFORE USING THESE FILTERS
I've determined that all of the excess spam I received after activating Postini was due to the fact that spammers were delivering directly to my mailserver and bypassing the Postini servers. This is likely due to one of the following:
1. They've cached the MX record I used to have and not looking up the new Postini record.
2. They're pinging 'mail.MYDOMAIN.xyz' and delivering there instead of to my MX since the 'mail' A record is commonly set to my mailserver.
To get around this I created the following two filters, one that allows all messages sent from Postini to enter my inbox and one that moves all other messages (messages not sent from Postini) to a Junk folder*.
The following instructions should only be used if your mail account is configured for Postini Spam Filtering.
Instructions for creating a filter can be found at
http://hostmysite.com/support/smartermail3/emailfilter/
Email Sent Through Postini Filter (filter 1):
1. On the criteria page, expand ‘Other’.
2. Check ‘Sent through a specific server (by IP)’ and click Next.
3. Under Criteria Details, enter the following range: 64.18.0.0-64.18.15.255 and click Next.
4. Enter a name for the rule, e.g. Email Sent Through Postini.
5. Under Actions, check ‘Move message to folder’ and select ‘Inbox’ from the drop down.
6. Click Save.
This filter will move all of the Postini messages to your inbox.
Email Not Sent Through Postini Filter (filter 2):
1. On the criteria page, expand ‘Contains Specific Words or Phrases’.
2. Check ‘Anywhere in Message’ and click Next.
3. Under Filter Type, select ‘OR’ and check ‘Use wildcards in search strings (* and ?)’.
4. Under Criteria Details, select ‘contains’, type @ in the text box and click Next.
5. Enter a name for the rule, e.g. Email Not Sent Through Postini.
6. Under Actions, check ‘Move message to folder’ and select a folder other than your Inbox from the drop down menu (it may be necessary to create a new folder for these messages).
7. Click Save.
This filter will move all messages that did not originate from Postini into the specified folder. We also recommend adding a prefix comment to the subject (an option under Actions in step 6) that says ‘Email Not Sent Through Postini’. This can be down to help you track messages that were caught by this filter.
NOTE: These filters should be the last two filters in your filter list. If you have existing filters, you will need to move these filters to the bottom of your filter list.
Something else you should be aware of is that if you have other domains on the same server or you have someone send you a message from your own domain then it will NOT go through postini because it will simply make a local delivery. In this case the above filters will catch legitimate mail.
To avoid this setup another filter to check for yourdomain.xyz (and any aliases as well) and have it move the mail message to the inbox.
Make sure this last filter is above your other postini filters.
*When your domain is configured for Postini, all email for your account is sent to the Postini server. Only users configured for Postini are filtered by Postini.
