Cisco 4700M Configuration Manual page 279

Chapter 4 Configuring TCP/IP Normalization and IP Reassembly Parameters
The order of precedence for the actions in this command is as follows:
1.
2.
3.
The keywords, options, and variables are as follows:
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•
•
•
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Table 4-2
Cisco 4700 Series Application Control Engine Appliance Security Configuration Guide
OL-16202-01
Configuring a Connection Parameter Map for TCP/IP Normalization and Termination
Drop
Clear
Allow
range—Specifies the TCP options not explicitly supported by the ACE using
a range of option numbers. This command enables you to allow or discard
segments associated with the TCP options specified in the option range.
number1—Lower limit of the TCP option range. Enter either 6 or 7 or an
–
integer from 9 to 255. See
– number2—Upper limit of the TCP option range. Enter either 6 or 7 or an
integer from 9 to 255. See
allow—Allows any segment with the specified option set.
drop—Used with the range or window-scale option only. Causes the ACE to
discard any segment with the specified option set.
selective-ack—Allows the ACE to inform the sender about all segments that
it received. The sender needs to retransmit the lost segments only, rather than
wait for a cumulative acknowledgement or retransmit segments
unnecessarily. Selective ACK (SACK) can reduce the number of
retransmitted segments and increase the throughput under some
circumstances.
timestamp—Measures the round-trip time (RTT) of a TCP segment between
two nodes on a network. Time stamps are always sent and echoed in both
directions.
window-scale—Allows the ACE to use a window scale factor that essentially
increases the size of the TCP send and receive buffers. The sender specifies a
window scale factor in a SYN segment that determines the send and receive
window size for the duration of the connection.
clear—Default for the explicitly supported options. Clears the specified
option from any segment that has it set and allows the segment.
lists the TCP options available for the tcp-options range command.
Table 4-2.
Table 4-2.
4-21