3com WX3000 Manuel D’Utilisation

 

2-2 

Enter 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. 

 

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, the device supports 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. 

To prevent the above mentioned problems, you can disable the device from sending such ICMP error 

packets. 

Follow these steps to disable sending of ICMP error packets: 

Enter system view 

— 

Disable sending of ICMP 
redirects 

Required 

Enabled by default 

Disable sending of ICMP 
destination unreachable 
packets 

Required 

Enabled by default