186
C
HAPTER
4: R
OUTER
C
OMMAND
R
EFERENCE
show icmp counters
Displays input and output counters for ICMP messages.
Traceroute-generated packets received by the RAS 1500 do not
increment the ICMP error counts Time Exceeded and Destination
Unreachable. Also, a number of ICMP error messages are sent to SYSLOG
hosts. The Receive Destination Unreachable event is sent to the console.
It lists the following:
INPUT COUNTERS
■
Messages
— ICMP packets received.
■
Errors
— ICMP packets received with errors.
■
Destination Unreachable
— Sum of ICMP messages received when a
router cannot forward a packet to its specified destination.
Error
messages
are s
ent to the console and CLI.
■
Time Exceeded
— Sum of ICMP messages generated by a router when
time has exceeded or a timeout has occurred while waiting for a
packet segment. Error messages sent to SYSLOG host.
■
Parameter Problems
— Sum of ICMP messages generated by a router
when it encounters an error.
Error messages
s
ent to SYSLOG host.
■
Source Quench
— Sum of ICMP messages informing a host it should
slow data transmission to ease congestion.
Error messages
s
ent to
SYSLOG host.
■
Redirects
— Sum of ICMP messages concerning a router advertising a
host of a better next hop.
Error messages
not logged.
■
Echos
— Sum of ICMP request messages received, signifying transport
system success.
■
Echo Replies
— Sum of ICMP reply messages received, indicating
transport system success.
■
Timestamps
— Sum of ICMP request messages received seeking time
from another machine for clock synchronization and estimated transit
time purposes.
Error messages
s
ent to SYSLOG host.
■
Timestamp Replies
— Sum of ICMP timestamp reply messages.
ICMP SETTINGS
ICMP Logging:
ENABLED
ICMP Router Advertise:Enabled
ENABLED