From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Chan Subject: Re: High number of concurrent connections causes 2.6.4 to go berserk Date: Fri, 02 Apr 2004 12:00:35 +0800 Sender: netdev-bounce@oss.sgi.com Message-ID: <406CE563.5090105@outblaze.com> References: <406CBA60.50103@outblaze.com> <406CDDF5.4070500@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: netdev@oss.sgi.com, Yusuf Goolamabbas Return-path: To: Nivedita Singhvi In-Reply-To: <406CDDF5.4070500@us.ibm.com> Errors-to: netdev-bounce@oss.sgi.com List-Id: netdev.vger.kernel.org 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 > > >