Users Guide

deny tcp
Congure a lter that drops transmission control protocol (TCP) packets meeting the lter 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 [bytes] [order] [fragments] [monitor [session-ID]] [no-drop]
To remove this lter, you have two choices:
• Use the no seq sequence-number command if you know the lter’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 /prex format (/x) or A.B.C.D. The mask, when specied 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 lter.
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 ag or combination of bits:
• ack: acknowledgement eld
• fin: nish (no more data from the user)
• psh: push function
• rst: reset the connection
• syn: synchronize sequence numbers
• urg: urgent eld
• established: datagram of established TCP session
Use the established ag to match only ACK and RST ags of established TCP
session.
You cannot use established along with the other control ags
While using the established ag in an ACL rule, all the other TCP control ags are
masked, to avoid redundant TCP control ags conguration in a single rule. When you use
any TCP control ag in an ACL rule, established is masked and other control ags are
available.
operator (OPTIONAL) Enter one of the following logical operand:
• eq = equal to
• neq = not equal to
• gt = greater than
• lt = less than
200 Access Control Lists (ACL)