D-Link DVX 1000 Product Manual - Page 86

Appendix A - Appendix Sending ICMP redirect messages For the same reason as mentioned above, it is not advisable to send ICMP redirect messages. Connections from IANA-reserved blocks IANA has generated a list of reserved blocks of IP Address, from/to where the connection is not allowed. ICMP Source Quench Messages An ICMP source quench is generated by a gateway or the destination host and tells the sending end to ease up because it cannot keep up with the speed at which it's receiving the data. This service is allowed. ICMP Parameter Problem Messages The ICMP Parameter Problem message is sent to the source host for any problem not specifically covered by another ICMP message. Receipt of a Parameter Problem message generally indicates some local or remote implementation error. These messages are allowed. ICMP Destination Unreachable/Service Unavailable Messages The Destination Unreachable message is an ICMP message which is generated by the router to inform the client that the destination host is unreachable, unless the datagram has a multicast address. Reasons for this message may include the physical connection to the host does not exist (distance is infinite), the indicated protocol or port is not active, or the data must be fragmented but the 'don't fragment' flag is on.This message is allowed. ICMP Time Exceeded Messages The ICMP time exceeded message is generated when the gateway processing the datagram (or packet, depending on how you look at it) finds the Time To Live field (this field is in the IP header of all packets) is equal to zero and therefore must be discarded. The same gateway may also notify the source host via the time exceeded message. ICMP Ping ICMP echo request and echo reply messages are allowed, by default. D-Link DVX-1000 User Manual 86