Disabling Icmp To Send Error Packets; Displaying And Maintaining Ip Performance Configuration - 3Com 4210 9-Port Configuration Manual

Table 2-2 Configure TCP attributes
Operation
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

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, Switch 4210 Family support sending ICMP redirect and destination unreachable packets.
Although sending ICMP error packets facilitate control and management, it still has the following
disadvantages:
Sending a lot of ICMP packets will increase network traffic.
If receiving a lot of malicious packets that cause it to send ICMP error packets, the device's
performance will be reduced.
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.
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
Enter system view
Disable sending ICMP redirects
Disable sending ICMP
destination unreachable
packets

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.
Command
system-view
tcp timer syn-timeout
time-value
tcp timer fin-timeout
time-value
tcp window window-size
Command
system-view
undo icmp redirect send
undo icmp unreach send
2-2
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.
Remarks
—
Required
Enabled by default
Required
Enabled by default