DDOS attack in my server ( I have installed sonicwall )

It is very interesting . I have installed sonicwall to protect my web server . but it seem someone can also attack my server .

when i type netstat -na
it show out many time_wait connection with many same IP though port 80 .
( pls see the pic whcih i have attached here )
but i think all of the IP is not a real IP .
Because i can not ping it back .

I have using Cobalt Raq550 server , but it seem it has no software or policy to prevent it .


Does anyone has solution on it ?
or .. what setting should i set in the soincwall ?

 

 

 

 

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