H3C Technologies H3C S3100 Series Switches - Manual (Page 115)

2-2
Table 2-2 Configure TCP attributes
Operation Command Remarks
Enter system view system-view —
Configure TCP synwait timer’s
timeout value tcp timer syn-timeout
time-value
Optional
By default, the timeout value is
75 seconds.
Configure TCP finwait timer’s
timeout value tcp timer fin-timeout
time-value
Optional
By default, the timeout value is
675 seconds.
Configure the size of TCP
receive/send buffer
tcp window window-size
Optional
By default, the buffer is 8
kilobytes.
Disabling ICMP to Send Error Packets
Sending error packets is a major function of ICMP protocol. In case of network abnormalities, ICMP
packets are usually sent by the network or transport layer protocols to notify corresponding devices so
as to facilitate control and management.
By default, S3100 Series Ethernet Switches support sending ICMP redirect and destination
unreachable packets.
Although sending ICMP error packets facilitate control and management, it still has the following
disadvantages:
z Sending a lot of ICMP packets will increase network traffic.
z If receiving a lot of malicious packets that cause it to send ICMP error packets, the device’s
performance will be reduced.
z As the ICMP redirection function increases the routing table size of a host, the host’s performance
will be reduced if its routing table becomes very large.
z If a host sends malicious ICMP destination unreachable packets, end users may be affected.
You can disable the device from sending such ICMP error packets for reducing network traffic and
preventing malicious attacks.
Table 2-3 Disable sending ICMP error packets
Operation Command Remarks
Enter system view system-view —
Disable sending ICMP redirects undo icmp redirect send
Required
Enabled by default
Disable sending ICMP
destination unreachable
packets
undo icmp unreach send
Required
Enabled by default
Displaying and Maintaining IP Performance Configuration
After the above configurations, you can execute the display command in any view to display the
running status to verify your IP performance configuration.