Administrator Guide

ICMP
Message Type
Keywords
ICMP Message Type Name
traceroute Traceroute
ttl-exceeded TTL exceeded
unreachable All unreachables
deny tcp
Configure a filter that drops transmission control protocol (TCP) packets meeting the filter criteria.
C9000 Series
Syntax
deny tcp {source mask | any | host ip-address} [bit] [operator port [port]]
{destination mask | any | host ip-address} [dscp] [bit] [operator port
[port]] [count [bytes]] [order] [fragments] [log [interval minutes]
[threshold-in-msgs [count]] [monitor]
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 tcp {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 are 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.
dscp Enter this keyword dscp to deny a packet based on the DSCP value. The range is
from 0 to 63.
bit Enter a flag or combination of bits:
● ack: acknowledgement field
● fin: finish (no more data from the user)
● psh: push function
● rst: reset the connection
● syn: synchronize sequence numbers
● urg: urgent field
operator (OPTIONAL) Enter one of the following logical operand:
● eq = equal to
● neq = not equal to
● gt = greater than
● lt = less than
● range = inclusive range of ports (you must specify two ports for the port
command)
port port
Enter the application layer port number. Enter two port numbers if using the range
logical operand. The range is from 0 to 65535.
The following list includes some common TCP port numbers:
Access Control Lists (ACL) 239