Google have recently released new features to the apps control panel for Gmail users.  These will allow users to replace Postini with some simple Gmail changes.

1. Restrict outbound mail for organisations.

As an example some schools choose to allow internal mail only for student organisations

• Sign in to the Google Apps administrator control panel.
• The URL is https://www.google.com/a/YOURDOMAIN, where YOURDOMAIN is the domain name you used to sign up for Google Apps.
• From the menu at the top of the page, select Advanced tools.
• The controls for restricting email delivery are in the Restrict email delivery section near the bottom of the page.
• Select the organizational units for which you want to restrict email delivery.

a. Click Add an organization.

b. Highlight an organizational unit whose users you want to apply the restriction to.

c. Click Add.

d. Repeat steps a through c for each organizational unit you want to apply the restriction to.

• To apply the restriction to all users, choose the top-level organizational unit, the one at the root of the organizational tree.
• Select the domains your users are allowed to exchange mail with.

a. Enter the domain name in the Allow email to or from these domains text box.

b. Click Add.

c. Repeat steps a and b for each permitted domain. (Don’t forget to include your domain to allow mail between users!)

2. Content Filters

You can create similar filters to those you might have used in Postini in the improved Google Apps control panel interface. For example you can create lists of blocked words or phrases and patterns of words.
You can choose to receive a notification of these breaches of policy, block the message, send it and alert, or modify the message.

For more information please visit the Help Center documentation for Objectionable Content and Content Compliance

To set up a new Content Compliance policy for an organisation:

Log in to the apps control panel,
Navigate to the settings pages, and email settings,
Select “org” settings and select an organisation.
In the Add Setting dialog box, click Content Compliance in the left navigation menu.
Edit each of the following sections: Messages to Affect, Conditions, and Consequences.
When you are finished making changes, click Add Setting to close the dialog box.

Note: Any settings you add will be highlighted on the Settings page.

Click Save changes at the bottom of the Settings page.

Consequences

This section enables you to specify what action to perform when a Content Compliance filter is triggered by a message.

Deliver to intended recipient
If you choose this setting, the message is delivered to the intended recipient despite the Content Compliance filter being triggered. Optionally, you can enter a prepend subject (for example, “[Content Compliance alert]”), as well as one or more extra header lines.

You also have the option to add others in your organization to the notification. Click Add, enter the email address, and optionally add a prepend subject and/or extra header. You can edit or delete email addresses from this notification by moving your cursor over the list.

Reject message
If you choose this setting, the message is rejected before it reaches the intended recipient, and the sender will receive a rejection notice. You have the option to edit the following default rejection notice: “Your email has been rejected because it violates company content compliance policy.”