Service Manual

access-lists. This mechanism copies all incoming or outgoing packets on one port and forwards (mirrors) them to
another port. The source port is the monitored port (MD) and the destination port is the monitoring port (MG).
deny tcp
Configure a filter that drops transmission control protocol (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] [order] [fragments] [threshold-in-msgs [count]]
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:
• 23 = Telnet
• 20 and 21 = FTP
156 Access Control Lists (ACL)