Administrator Guide

When you use the log option, the CP processor logs detail the packets that match. Depending on how
many packets match the log entry and at what rate, the CP may become busy as it has to log these
packets’ details.
The monitor option is relevant in the context of flow-based monitoring only. For more information, see
Port Monitoring.
The C-Series and S-Series cannot count both packets and bytes, when you enter the count byte options,
only bytes are incremented.
NOTE: When you configure ACL logging and byte counters simultaneously, byte counters may display
an incorrect value. Configure packet counters with logging instead.
Related
Commands
● deny tcp — assign a filter to deny TCP packets.
● deny udp — assign a filter to deny UDP packets.
● ip access-list extended — create an extended ACL.
deny icmp
To drop all or specific internet control message protocol (ICMP) messages, configure a filter.
Syntax
deny icmp {source mask | any | host ip-address} {destination mask | any
| host ip-address} [type] [ttl operator] [dscp] [count [byte] [order]
[fragments] [monitor] [no-drop]
To remove this filter, you have two choices:
● Use the no seq sequence-number command if you know the filter’s sequence number.
● Use the no deny icmp {source mask | any | host ip-address} {destination
mask | any | host ip-address} command.
Parameters
source Enter the IP address of the network or host from which the packets were sent.
mask Enter a network mask in /prefix format (/x) or A.B.C.D. The mask, when specified
in A.B.C.D format, may be either contiguous or non-contiguous.
any Enter the keyword any to specify that all routes are subject to the filter.
host ip-address Enter the keyword host then the IP address to specify a host IP address.
destination Enter the IP address of the network or host to which the packets are sent.
type Enter the ICMP packet type. The following types are available:
For IPv4:
echo count
echo-reply count
host-unreachable count
host-unknown count
network-unknown count
net-unreachable count
packet-too-big count
parameter-problem count
port-unreachable count
source-quench count
time-exceeded count
For IPv6:
echo count
echo-reply count
nd-ns count
nd-na count
packet-too-big count
190 Access Control Lists (ACL)