From owner-freebsd-stable Sat Mar 18 3: 3:29 2000 Delivered-To: freebsd-stable@freebsd.org Received: from dorifer.heim3.tu-clausthal.de (dorifer.heim3.tu-clausthal.de [139.174.243.252]) by hub.freebsd.org (Postfix) with ESMTP id 7536837B5A7 for ; Sat, 18 Mar 2000 03:03:26 -0800 (PST) (envelope-from olli@dorifer.heim3.tu-clausthal.de) Received: (from olli@localhost) by dorifer.heim3.tu-clausthal.de (8.9.3/8.9.3) id MAA22856; Sat, 18 Mar 2000 12:03:25 +0100 (CET) (envelope-from olli) Date: Sat, 18 Mar 2000 12:03:25 +0100 (CET) Message-Id: <200003181103.MAA22856@dorifer.heim3.tu-clausthal.de> From: Oliver Fromme To: freebsd-stable@FreeBSD.ORG Reply-To: freebsd-stable@FreeBSD.ORG Subject: Re: How to force remote reboot of 3.4-Release? X-Newsgroups: list.freebsd-stable In-Reply-To: <8as4d9$1beh$1@atlantis.rz.tu-clausthal.de> User-Agent: tin/1.4.1-19991201 ("Polish") (UNIX) (FreeBSD/3.4-19991219-STABLE (i386)) MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit Sender: owner-freebsd-stable@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Michael Robinson wrote in list.freebsd-stable: > Last night, I was running a very large Postgresql query on one of my > colocated development servers when all of a sudden the session completely > froze. Since then, I can get TCP connections to all the open ports, but > they just hang with no services ever coming up. Ping works fine. I have once written a small kernel hack which I called "ICMP REBOOT". When you send a certain ICMP packet from a certain host or network, the machine logs the host and panics. The packet can be sent with a modified ping command. It is very useful, because the reception of ICMP packets is performed by the kernel on the lowest level in the interrupt handler, which means that there's a good chance that it will still work, even if the system is pretty much dead. This hack saved my life a few times. ;) I considered submitting the patch, but I guess it wouldn't be committed because it's a "dirty hack". Someone else who has access to your network could easily reboot your box using IP- spoofing, because it's authenticated by IP addresses only. It's probably a good idea to use it behind a firewall that drops unknown ICMP packets. If someone is interested, I've put the hack online here: http://www.fromme.com/icmpreboot.tar.gz Please read the README file. Use at your own risk. Regards Oliver -- Oliver Fromme, Leibnizstr. 18/61, 38678 Clausthal, Germany (Info: finger userinfo:olli@dorifer.heim3.tu-clausthal.de) "In jedem Stück Kohle wartet ein Diamant auf seine Geburt" (Terry Pratchett) To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message