CLI Guide

Related
Commands
● ip access-list extended — create an extended ACL.
●
● permit tcp — assign a permit filter for TCP packets.
● permit udp — assign a permit filter for UDP packets.
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
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.
● gt(greater than) — matches packets that contain a ttl value that is greater
than the specified ttl value.
● lt (less than) — matches packets that contain a ttl value that is less than the
specified ttl value.
● range(inclusive range of values) — matches packets that contain a ttl value
that falls between the specified range of ttl values.
dscp Enter the keyword dscp to permit a packet based on the DSCP value. The range is
from 0 to 63.
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
parameter)
Access Control Lists (ACL) 209