Enabling Outbound DNS Traffic

How to configure ISA Server for Outbound Mail
B. Enabling Outbound DNS Traffic

To allow Exchange to send mail to Internet addresses, you must create an access rule on the ISA Server computer that allows outbound DNS queries from the DNS server.

Note: if you want to limit the access rule so that it applies only to the DNS server or Exchange server, create a Computer or Computer Set network object that contains only those servers.

1. In the Microsoft ISA Server Management console tree, select Firewall Policy.

2. In the task pane, on the Tasks tab, select Create New Access Rule to start the New Access Rule Wizard.

3. On the Welcome page of the wizard, enter the name for the access rule, such as Outbound DNS, and then click Next.

4. On the Rule Action page, select Allow, and then click Next.

5. On the Protocols page, in This rule applies to, select Selected protocols and then use the Add button to open the Add Protocols dialog box.

6. In the Add Protocols dialog box, expand Common Protocols, and select DNS. Click Add, and then click Close, to close the Add Protocols dialog box. On the Protocols page, click Next.

7. On the Access Rule Sources page, click Add to open the Add Network Entities dialog box, select the Computer or Computer Set network object you created previously, click Add, and then click Close. On the Access Rule Sources page, click Next.

8. On the Access Rule Destinations page, click Add to open the Add Network Entities dialog box, click Networks, select the External network (representing the Internet), click Add, and then click Close. On the Access Rule Destinations page, click Next.

9. On the User Sets page, you can specify the set of users whose credentials are used by the servers that require access, or you can leave the default user set All Users. If you want to specify a specific user set, select All Users and click Remove. Then, use the Add button to open the Add Users dialog box, from which you can add the user set to which the rule applies. The Add Users dialog box also provides access to the New User Sets Wizard through the New menu item. When you have completed the user set selection, click Next.

10. Review the information on the wizard summary page, and then click Finish.

11. In the Firewall Policy details pane, click Apply to apply the new access rule. It may take a few moments for the rule to be applied. Remember that access rules are ordered, so if a deny rule matching SMTP access requests exists ahead of this allow rule in the order, access will be denied.

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