Command Line Reference Guide

Access Control Lists (ACL) | 231
deny tcp
c e s
Configure a filter that drops TCP packets meeting the filter criteria.
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 [byte] | log] [order] [monitor]
[fragments]
To remove this filter, you have two choices:
• Use the no seq sequence-number command syntax if you know the filter’s sequence number or
• 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 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 followed by the IP address to specify a host IP
address.
dscp
Enter this keyword to deny a packet based on DSCP value.
Range: 0-63
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 parameter.
port port
Enter the application layer port number. Enter two port numbers if using the
range logical operand.
Range: 0 to 65535.
The following list includes some common TCP port numbers:
• 23 = Telnet
• 20 and 21 = FTP
• 25 = SMTP
• 169 = SNMP
destination
Enter the IP address of the network or host to 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.
count (OPTIONAL) Enter the keyword count to count packets processed by the
filter.