Authenticated Bypass Rules

Authenticated bypass rules are firewall rules that will allow a connection even though the existing firewall rules in Windows Firewall with Advanced Security would block the connection. Specifically, authenticated bypass rules let you block a particular type of traffic using firewall rules while allowing authenticated users or computers to bypass the block. A typical use for authenticated bypass rules is to allow network scanners and intrusiondetection systems to run on computers running Windows and to not have Windows Firewall with Advanced Security block their functionality.

Authenticated bypass rules require that the network traffic from the authorized computers be authenticated using IPsec so that identity can be confirmed. Authenticated bypass can be configured for inbound firewall rules, not outbound rules. However, you can specify override block rules in conjunction with authenticated outbound rules. The difference is that for the outbound rules, you don't have to specify remote machines, while for inbound rules you have to specify either remote machines or users.

For example, to enable authenticated bypass for the example rule discussed previously, select Override Block Rules in Figure 26-6 and then modify the filtering conditions for the rule to specify an authorized computer, user, or group of computers or users. Note that specifying users or user groups does not suffice-you must specify a computer or a computer group. Specifying only a user or user group for an inbound override block rule does not allow the rule to be configured and displays the error message "Rules that override block rules must specify at least one computer or computer group for authorization." Note also that if you do specify a computer or computer group, you may also specify users or user groups. For more information on how to configure authenticated bypass rules, see the section titled "Creating and Configuring Firewall Rules" later in this tutorial. For additional information, see http://technet.microsoft.com/en-us/library/cc753463.aspx.