topic TCP SYN Cookie Protection parameter in Operating System - HP-UX

TCP SYN Cookie Protection parameter

tcp sequence numbers co — Tue, 17 Nov 2009 16:29:29 GMT

I'm trying to protect against a "SYN Attack" and would like to no what prarameter setting I need to make and in what file (/etc/rc.config.d/nddconf)?

Re: TCP SYN Cookie Protection parameter

Steven E. Protter — Tue, 17 Nov 2009 17:01:39 GMT

Shalom,

Your best bet is to filter the traffic through a real firewall prior to letting it go to your HP-UX system.

ipfilter firewall can also be useful in these circumstances.

SEP

Re: TCP SYN Cookie Protection parameter

tcp sequence numbers co — Tue, 17 Nov 2009 17:08:43 GMT

Shalom,
The information that you provided was not useful. I'm looking for the parameter setting within the nddconf file.

Re: TCP SYN Cookie Protection parameter

BUPA IS — Thu, 19 Nov 2009 16:59:05 GMT

Hello,
The value you need to tune is
tcp_syn_rcvd_max

You can see the current value setting with

ndd -get /dev/tcp tcp_syn_rcvd_max
also see man ndd and run the command:

ndd -h supported

which displays the list of supported parameters you can edit .
The supplied values work in nearly all cases
I would recommend that you only adjust them if you need to fix a very specific problem.

Mike