From owner-freebsd-questions Sat Apr 10 6:31:41 1999 Delivered-To: freebsd-questions@freebsd.org Received: from janus.syracuse.net (janus.syracuse.net [205.232.47.15]) by hub.freebsd.org (Postfix) with ESMTP id B336114D28; Sat, 10 Apr 1999 06:31:37 -0700 (PDT) (envelope-from green@unixhelp.org) Received: from localhost (green@localhost) by janus.syracuse.net (8.9.2/8.8.7) with ESMTP id JAA69978; Sat, 10 Apr 1999 09:29:19 -0400 (EDT) Date: Sat, 10 Apr 1999 09:29:19 -0400 (EDT) From: Brian Feldman X-Sender: green@janus.syracuse.net To: Dmitry Valdov Cc: chris@calldei.com, freebsd-current@FreeBSD.ORG, freebsd-questions@FreeBSD.ORG Subject: Re: DoS from local users (fwd) In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, 10 Apr 1999, Dmitry Valdov wrote: > > > On Sat, 10 Apr 1999, Chris Costello wrote: > > > Date: Sat, 10 Apr 1999 02:05:33 -0500 > > From: Chris Costello > > Reply-To: chris@calldei.com > > To: Dmitry Valdov > > Cc: freebsd-current@FreeBSD.ORG, freebsd-questions@FreeBSD.ORG > > Subject: Re: DoS from local users (fwd) > > > > On Sat, Apr 10, 1999, Dmitry Valdov wrote: > > > > You typically want to set a restriction as to how many > > > > processes a user can spawn. This is done by editing > > > > /etc/login.conf and changing the user's login class, see the man > > > > page for 'login.conf'. > > > > > > > > > > I'm about CPU usage, not about many processes. > > > See: > > > CPU states: 17.8% user, 0.0% nice, 81.7% system, 0.5% interrupt, 0.0% > > > idle > > > on any (tested on P2-45) machine. > > > > > > CPU is used by SYSTEM, not by USER. So I can't restrict it with login.conf > > > And load average can be up to 20-40 :( > > > > > > Please don't redirect me to -questions, it's a kernel problem, not just > > > config. > > > > How is it a kernel problem? It's a forkbomb. It spawns many > > processes. You can also limit CPU usage with login.conf, I > > believe. > > Hmm. How I can limit CPU usage by SYSTEM? See top's output below. > > Dmitry. > > PS. I've just tried it. And I'm right - CPU usage limit can't help. > So? Processes that run a while go down in priority [McKusick95 I believe, THE book] so they are preempted easily. Look in top and see if they're all at the top of the list. I bet they're not! Also, you can set per-user niceness levels, and why are you being so liberal giving a standard LUSER 32 processes? This is a system administration problem. > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-current" in the body of the message > Brian Feldman _ __ ___ ____ ___ ___ ___ green@unixhelp.org _ __ ___ | _ ) __| \ FreeBSD: The Power to Serve! _ __ | _ \__ \ |) | http://www.freebsd.org _ |___/___/___/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message