Alex Feigenson's Blog Systems Administrator That Communicates Effectively

8Feb/102

Sync Active Directory with Postini

About a year ago I had the opportunity to set up Postini for my organization as a part of my Exchange 2007 setup/migration.

I selected Postini as our anti-spam service - mainly because our users were already used to the interface. One of the biggest challenges during planning was how to keep Postini current with my organizations mailboxes. I could let Postini create an account when an email is received, but that sounded like a really bad idea. Thankfully, in my research I found out about an application that will sync AD to Postini: Google Apps Directory Sync for Email Security.

The tool isn't overly difficult to set up, but it does have a few quirks that I feel I should share - especially since Postini's paid support is awful. We paid $750 for support and when I needed help getting it working I was informed that they didn't support syncing and referred me to knowledge base articles. I managed to figure it out on my own (on time!) and I've had it working perfectly ever since. Below you can find some set up information that may help you. Please keep in mind that this setup works in my environment and may not work in yours.

Once you download the application (link above), you will need to create a "profile" that you will use to run the syncing application.

The first screen you will see is Authentication. This is where you input your administrator login for your Postini organization.

The second screen you will see is Orgs - you can select a specific organization to sync to (for instance, if you had multiple domains). I have it set to "All users in all orgs under your account," and it works perfectly with a 3 org nested setup like mine.

Exclusion filters. I don't use these, but it will allow you to exempt accounts from being syncronized.

LDAP settings: This is where you input your Active Directory information. You can use either LDAP or LDAPS (SSL LDAP). If you opt to use LDAPS, don't forget to change the port to 636. Input a domain controller IP under Host Name, add in your base domain - for example: DC=subdomain,DC=domain,DC=com. Authentication is an account with read access to your AD - use the DOMAIN\user format.

For LDAP User Attributes, select MS Active Directory. The email address attribute is "mail." Alias Address Attributes are "proxyAddresses."

For user sync - this is an important part: If you don't add a search string for users, it will also pull computer accounts. It won't add them, but it will error your log report. I added my Org Name, SUBTREE, (sAMAccountType=805306368) - this will filter out everything, but users. You could add any kind of filter you wanted here. More about LDAP filters.

Mailing Lists - I don't sync them. They are almost all internal only. Since you have to also make a change in Exchange 2007 to allow for non-authenticated users, I make exceptions for dist lists through the web interface for public facing mailing lists. This is up to you.

Notification - This will email you a report every time it runs that tells you if there were any errors, how many users were added/removed, etc. I recommend this.

Delete limit - I have this left at the default 5% - I can see the wisdom in this setting ;)

Log files - lets you set the file path/limit on the synchronization log. I left as is.

Now you should be done. Go ahead and run the sync simulation. At the bottom of the log in the Sync Log tab, you should see: Simulation completed successfully - good job! Go ahead and save the profile by going to the file menu to a location you will remember easily.

The sync tool will not run automatically on its own - and for that I set up a scheduled task that runs every day at midnight and runs a cmd script that contains the following:

sync-cmd -a -c emailsync.xml
WAIT

sync-cmd is located in your Postini sync tool location - most likely C:\Program Files\Google Apps Directory Sync for Email Security. The -a option commits the changes and the -c option specifies the configuration file you created above. Voila! Every midnight you should get an email letting you know what has changed.

Hope that helps!

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Comments (2) Trackbacks (0)
  1. Hi Alex,
    I read your interesting post. I evaluating postini form my business. What is your experience? It’s a good antispam?

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  2. There are good things and there are bad things with Postini, but it’s overwhelmingly on the good side of things. The administration interface is absolutely terrible, but the filtering is top notch. It’s so good that I get emails occasionally from people pointing out when it fails and a spam gets through – and that happens maybe once every couple of months.

    We considered using a hardware appliance or a software package, but the other benefit to Postini is it does mail spooling – if your mail server goes offline, they will buffer email until you come back online.

    Hope that helps,
    Alex

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