Re: Why is ReGet breaking things?

From: Sergey Kubushin (ksi@ksi-linux.com)
Date: Fri Feb 11 2000 - 09:42:47 EST


On Fri, 11 Feb 2000, Jim Nance wrote:

> On Thu, Feb 10, 2000 at 09:29:46PM +0200, Sergey Kubushin wrote:
> >
> > I can kill any of them. Have you heard, e.g. for such thing like a ReGet for
> > windoze? Have you seen how this "smart" program opens 300+ ftp sessions for
> > a same file which is happened to be a 600+ Mbyte image of a distribution
> > CD? And it's not the end of the intelligence of a beast, it sends an ABORT
> > after each portion got (several Kbytes) and then tries to reget from the
> > aborted position. They are smart, they do know they will get the file even
> > the connection is flaky... I don't even know how to combat this other then
> > filtering those who has been caught redhanded out...
>
> Does this kill a Linux server? I dont think it should. It would be
> interesting to put together a test program that did this (I dont have
> ReGet or a windows machine for that matter) and see what is falling apart.

This does kill ANY machine. Tested here with AIX and Solaris. System is
going out of memory, FDs etc. LA skyrockets to absolutely crazy figures (the
last I did see was 498) and system dies. You're lucky if you're able to
"killall in.ftpd", 'coz usually any attempt to run any program results in
"Unable to load interpreter"...

It's not that kernel dies, the system is simply goes outta resources...

===========================================================================
Sergey Kubushin aka the Tamer < > The impossible we do immediately.
e-mail: ksi@ksi-linux.com SK320-RIPE < > Miracles require 24-hour notice.
===========================================================================

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