Configuring Tcp Optional Parameters - 3Com MSR 50 Series Configuration Manual

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Configuring TCP
Optional Parameters
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To do...
Configure the maximum of
TCP connections in a state
Configure the TCP state check
interval
With the protection against Naptha attack enabled, the device will periodically
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check and record the number of TCP connections in each state.
With the protection against Naptha attack enabled, if the device detects that
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the number of TCP connections in a state exceeds the maximum number, the
device will consider that there is a Naptha attack and accelerate the aging of
these TCP connections. The device will not stop accelerating the aging of TCP
connections until the number of TCP connection in such a state is less than
80% of the maximum number.
TCP optional parameters that can be configured include:
synwait timer: When sending a SYN packet, TCP starts the synwait timer. If no
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response packets are received within the synwait timer timeout, the TCP
connection is not successfully created.
finwait timer: When the TCP connection is in FIN_WAIT_2 state, finwait timer
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will be started. If no FIN packets are received within the timer timeout, the TCP
connection will be terminated. If FIN packets are received, the TCP connection
state changes to TIME_WAIT. If non-FIN packets are received, the system
restarts the timer from receiving the last non-FIN packet. The connection is
broken after the timer expires.
Size of TCP receive/send buffer
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Follow these steps to configure TCP optional parameters:
To do...
Enter system view
Configure TCP synwait timer's
timeout value
Configure TCP finwait timer's
timeout value
Configure the size of TCP
receive/send buffer
CAUTION: The actual length of the finwait timer is determined by the following
formula: Actual length of the finwait timer = (Configured length of the finwait
timer - 75) + configured length of the synwait timer.
Use the command...
tcp state { closing |
established | fin-wait-1 |
fin-wait-2 | last-ack |
syn-received }
connection-number number
tcp timer check-state
timer-value
Use the command...
system-view
tcp timer syn-timeout
time-value
tcp timer fin-timeout
time-value
tcp window window-size
Configuring TCP Attributes
Remarks
Optional
5 by default.
If the maximum number of
TCP connections in a state is
0, the aging of TCP
connections in this state will
not be accelerated.
Optional
30 seconds by default.
Remarks
-
Optional
By default, the timeout value
is 75 seconds.
Optional
By default, the timeout value
is 675 seconds.
Optional
By default, the buffer is 8
kilobytes.
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