Viewing ICMP Group Statistics
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Address Mask Request
The number of ICMP Address Mask Request Messages received, according to the
icmpInAddrMasks.
Address Mask Reply
The number of ICMP Address Mask Reply messages received, according to the
icmpInAddrMaskReps. To determine the network subnet mask, a machine can issue
an address mask request, either targeted to a specific address or a broadcast to the
entire network. A responding machine includes the network subnet mask in an
address mask reply.
ICMP Transmitted Message Statistics
Total Messages
The total number of ICMP messages which this entity attempted to send,
including all those counted by icmpOutErrors. This field displays icmpOutMsgs.
Errors
The number of ICMP messages which this entity did not send due to problems
discovered within ICMP such as lack of buffers, according to the icmpOutErrors.
OutErrors indicates the number of ICMP messages that were queued for
transmission and then not transmitted due to problems discovered by ICMP.
This value should not include errors discovered outside the ICMP layer such as
the inability of IP to route the resultant datagram. In some implementations there
may be no types of error which contribute to this counter’s value.
Destination Unreachable
The number of ICMP Destination Unreachable messages sent, according to the
icmpOutDestUnreachs. A gateway issues a destination unreachable message when
it cannot deliver a datagram due to one of the following causes:
• network, host, protocol, or port was unreachable
• fragmentation was necessary but disallowed by the “don’t fragment” bit
• source route failed
• destination network or host unknown
• source host isolated
• communication with destination network or host administratively prohibited
• network or host unreachable for type of service
Time Exceeded
The number of ICMP Time Exceeded messages sent, according to the
icmpOutTimeExcds. When a device discards a datagram because the time-to-live
counter (hop count) reached zero, or because the reassembly counter expired
while waiting for fragments, a router sends a time exceeded message to the
station that transmitted the original datagram. A time exceeded message can
indicate an excessively long route from source to destination, or a circular route
due to errors in the routing tables. For fragmented packets, the receiving station
starts its reassembly timer when it receives the first fragment of a fragmented