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