Administrator Guide

Usage Information
The order option is relevant in the context of the Policy QoS feature only. For more information, refer to the
Quality of Service chapter of the FTOS Configuration Guide.
When you use the log option, the CP processor logs details about 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, refer to Port
Monitoring.
NOTE: When ACL logging and byte counters are configured simultaneously, byte counters may
display an incorrect value. Configure packet counters with logging instead.
permit tcp
To pass TCP packets meeting the filter criteria, configure a filter.
Syntax
permit tcp {source mask | any | host ip-address} [bit] [operator port [port]]
{destination mask | any | host ip-address} [bit] [ttl operator] [dscp]
[operator port [port]] [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 permit 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 then the IP address to specify a host IP address.
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
• established: datagram of established TCP session
Use the established flag to match only ACK and RST flags of established TCP
session.
You cannot use established along with the other control flags
While using the established flag in an ACL rule, all the other TCP control flags are
masked, to avoid redundant TCP control flags configuration in a single rule. When you use
any TCP control flag in an ACL rule,
established is masked and other control flags are
available.
ttl Enter the keyword ttl to permit a packet based on the time to live value. The range is
from 1 to 255.
operator Enter one of the following logical operand:
• eq(equal to) — matches packets that contain a ttl value that is equal to the specified
ttl value.
• neq(not equal to) — matches packets that contain a ttl value that is not equal to the
specified ttl value.
Access Control Lists (ACL) 203