IP source routing is a mechanism that allows the sender to determine the IP route that a datagram should take through the network. Microsoft recommends to configure this setting to Not Defined for enterprise environments and to Highest Protection for high security environments to completely disable source routing. HKLM\System\CurrentControlSet\Services\Tcpip\Parameters\DisableIPSourceRouting Vulnerability: Source routing allows a computer that sends a packet to specify the route that the packet takes. Attackers can use source routed packets to obscure their identity and location. Countermeasure: Configure the DisableIPSourceRouting entry to a value of 2. Potential impact: If you configure this value to 2, all incoming source routed packets will be dropped. Fix: (1) GPO: Computer Configuration\Windows Settings\Security Settings\Local Policies\Security Options\MSS: (DisableIPSourceRouting) IP source routing protection level (protects against packet spoofing) (2) REG: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Tcpip\Parameters!DisableIPSourceRouting