Date: Sat, 18 Mar 2000 12:03:25 +0100 (CET) From: Oliver Fromme <olli@dorifer.heim3.tu-clausthal.de> To: freebsd-stable@FreeBSD.ORG Subject: Re: How to force remote reboot of 3.4-Release? Message-ID: <200003181103.MAA22856@dorifer.heim3.tu-clausthal.de> In-Reply-To: <8as4d9$1beh$1@atlantis.rz.tu-clausthal.de>
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Michael Robinson <robinson@netrinsics.com> 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
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