Firewall Rule Properties - Customize ICMP Settings
Applies To: Windows Server 2008
ICMP Properties
Use this dialog box to configure criteria based on the Internet Control Message Protocol (ICMP).
All ICMP types
This specifies any message using the ICMP protocol.
Specific ICMP types
Use this to select one or more ICMP message types.
This ICMP type
Use this to specify any ICMP message type that is not provided by the ICMP Properties dialog box. Click Add to List to add the type to the list.
Type
This is a number that correlates to an ICMP message type. For example, 3 is the number for the "Destination Unreachable" message.
Code
This is a number that correlates to a code for an ICMP message type. These codes are details that are useful for troubleshooting and understanding the circumstances that prompted the sending of the message. The same code number can mean different things for different message types. For example, 3 is the code for "Port Unreachable" for the "Destination Unreachable" message, but it is also the code for "Redirect Datagram for the Type of Service and Host" for the "Redirect" message type.
By combining the message type and code, you can specify very detailed criteria for the exception. One use for this would be to make sure specific ICMP messages pass through Windows Firewall with Advanced Security for remote troubleshooting, while blocking other ICMP messages.