Re: performance of libnet-based tools

On Fri, Feb 25, 2005 at 11:07:12PM -0800, Steven Alexander Jr. wrote:
> I've been experimenting with a few different
> libnet-based tools such as Packit and ISIC.  If I try
> to generate a high-volume of traffic using these
> tools, with various options and protocols, the error
> rate is extremely high.  ISIC says:
>
> Failed to send packet: No buffer space available
>
> The synflood tool that comes as a libnet sample works
> for several seconds and begins reporting:
>
> libnet_write: libnet_write_raw_ipv4(): -1 bytes
> written (Host is down)
>
> I'm not sure where the problem lies and I would love
> to hear any suggestions.  I'm using a 3.0Ghz P4 with
> 1.5G RAM and a $20 Linksys FA311 card on FreeBSD 5.3
> and a 1.3GHZ AMD laptop with 512MB RAM and a built-in
> Realtek RTL8139C+ card on FreeBSD 4.9.  
>
> Do I need to tune the OS?  Do I need a better network
> card?
>
> I'd like to be able to perform various stress testing
> exercises on my test network.  

I'm also very interested in those tests. Can you tell us more please?

Now, I'll try to answer some of your questions.

"Failed to send packet: No buffer space available" : this may be
caused because the driver's buffer is full. 

" libnet_write: libnet_write_raw_ipv4(): -1 bytes written (Host is
down)" :
here, that may be because the remote host is really down ? I mean some
OS do not feel very well under synflood. 

That is just guesses ... I may be mistaken ...

A+
        Fred Raynal