GEN:SID 1:400
Message ICMP Destination Unreachable Network Unreachable for Type of Service
Summary This event is generated when An ICMP Network Unreachable For Type Of Service datagram is detected on the network.  
Impact Routers will generate this message when the route to the destination network does not support the Type of Service requested in the datagram or the default TOS.  This could be an indication or routing problems or excessive packet loss.
Detailed Information This rule generates informational events about the network.  Large numbers of these messages on the network could indication routing problems, faulty routing devices, or improperly configured hosts.
Affected Systems  
Attack Scenarios None Known
Ease of Attack Numerous tools and scripts can generate these types of ICMP datagrams.
Corrective Action This rule detects informational network information, no corrective action is necessary.
Additional References None