syn flooding

[Saraswathi Venkataraman <sa...@Xoriant.Com>]

I have configured my TS as forward transparent proxy. I generate requests to the TS server and measure the TPS with objects of different sizes from the webserver. For small objects, say 2k objects, I get TPS as 12k with small ram cache, and as high as 50K with large ram cache. However with typical and large objects(17k,1.1MB) the TPS I get for both is the same. And when I run with the large cache, requests for typical and large objects I get kernel: possible SYN flooding on port 80. 
> Sending cookies. Error in /var/log/messages

Any idea how I can resolve this?

Thanks & Regards
Saraswathi Venkataraman | Xoriant Solutions Pvt. Ltd.  
Winchester, Hiranandani Business Park, Powai, Mumbai 400076, INDIA. 
Tel: +91 22 30511000 | Ext: 1113 | http://www.xoriant.com

Re: syn flooding

[Gmail <un...@gmail.com>]

edit your /etc/sysctl.conf and change

net.ipv4.tcp_syncookies = 1

to

net.ipv4.tcp_syncookies = 0

then sysctl -p

syncookies can be evil, when enabled window scaling is effectively disabled.

best
-Kev


On Wed, Jun 6, 2012 at 7:13 AM, Saraswathi Venkataraman
<sa...@xoriant.com> wrote:
> I have configured my TS as forward transparent proxy. I generate requests to the TS server and measure the TPS with objects of different sizes from the webserver. For small objects, say 2k objects, I get TPS as 12k with small ram cache, and as high as 50K with large ram cache. However with typical and large objects(17k,1.1MB) the TPS I get for both is the same. And when I run with the large cache, requests for typical and large objects I get kernel: possible SYN flooding on port 80.
>> Sending cookies. Error in /var/log/messages
>
> Any idea how I can resolve this?
>
> Thanks & Regards
> Saraswathi Venkataraman | Xoriant Solutions Pvt. Ltd.
> Winchester, Hiranandani Business Park, Powai, Mumbai 400076, INDIA.
> Tel: +91 22 30511000 | Ext: 1113 | http://www.xoriant.com