Chapter40 More About....
Services and Ports
40-10
Cisco Router and Security Device Manager 2.5 User’s Guide
OL-4015-12
ICMP Message Types
ICMP Messages Port Number Description
alternate-address 6 Alternate host address.
conversion-error 31 Sent to report a datagram conversion error.
echo 8 Type of message sent when ping command is issued.
echo-reply 0 Response to an echo-request (ping) message.
information-reply 16 Obsolete. Response to message sent by host to discover number
of the network it is on. Replaced by DHCP.
information-request 15 Obsolete. Message sent by host to discover number of the
network it is on. Replaced by DHCP.
mask-reply 18 Response to message sent by host to discover network mask for
the network it is on.
mask-request 17 Obsolete. Message sent by host to discover network mask for
the network it is on.
mobile-redirect 32 Mobile host redirect. Sent to inform a mobile host of a better
first-hop node on the path to a destination.
parameter-problem 12 Message generated in response to packet with problem in its
header.
redirect 5 Sent to inform a host of a better first-hop node on the path to a
destination.
router-advertisement 9 Sent out periodically, or in response to a router solicitati on.
router-solicitation 10 Messages sent in orde r to prompt routers to generate router
advertisements messages quickly.
source-quench 4 Sent when insufficient buffer space is available to queue
packets for transmission to next hop, or by destination router
when packets are arriving too quickly to be processed.
time-exceeded 11 Sent to indicate received packet’t time to live field has reached
zero.
timestamp-reply 14 Reply to request for timestamp to be used for synchronization
between two devices.