Re: High number of concurrent connections causes 2.6.4 to go berserk

[Christopher Chan <cchan@xxxxxxxxxxxx>]

Nivedita Singhvi wrote:
> Christopher Chan wrote:
>
> > When tcp_max_syn_backlog is set to 4096 and
> > route.max_size = 131072
> > route.gc_thresh = 65536
> >
> > the box goes berserk almost immediately after bootup due to a bounce 
> > flood hitting the box.
>
> > The below values seem to workaround whatever problem the kernel has.
> >
> > tcp_max_syn_backlog = 2048
> > route.max_size = 1048576
> > route.gc_thresh = 65536
>
> Did you try just one of the first two and see which
> one actually made a difference? I'm assuming the first,
> but that might not be the case..
Another box that has less traffic but sometimes gets ddosed by bounces 
has default settings
tcp_max_syn_backlog = 1024
route.max_size = 131072
route.gc_thresh = 8192

This box's 2.6.4 also went berserk during the ddos.

I'll try your suggestion and get back to you.

> thanks,
> Nivedita