From owner-freebsd-questions Fri Nov 12 4:48:25 1999 Delivered-To: freebsd-questions@freebsd.org Received: from isy.liu.se (ns.isy.liu.se [130.236.48.2]) by hub.freebsd.org (Postfix) with ESMTP id E37D414C25 for ; Fri, 12 Nov 1999 04:48:20 -0800 (PST) (envelope-from mj@isy.liu.se) Received: from lagrange.isy.liu.se (lagrange.isy.liu.se [130.236.49.127]) by isy.liu.se (8.9.1/8.9.1) with ESMTP id NAA14209; Fri, 12 Nov 1999 13:48:09 +0100 (MET) Message-ID: X-Mailer: XFMail 1.3 [p0] on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <9911120731257C.11943@weba4.iname.net> Date: Fri, 12 Nov 1999 13:48:15 +0100 (CET) From: Micke Josefsson To: os2_daemon@altavista.net Subject: RE: FreeBSD security on TCP/IP question. Cc: freebsd-questions@FreeBSD.ORG Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 12-Nov-99 os2_daemon@altavista.net wrote: > Hello, > I've just ran into trouble for mucking around with ifconfig and conflicting > IP addresses. I'm just an ordinary user without any deep TCP/IP knowledge. > > It all started when curiously, I tried to put 172.16.1.1 which is an NT > server into ifconfig. Ifconfig said some error messages that the IP address > have been taken by another machine. Who cares ... The net cares quite a big deal... Never let two machines have the same IP address. And don't try to invent your own, the IP address must be in your net's nameserver to work properly. > Next day, the sysadmin came to me and accusing me for trying to hijack the > system. He told me that apparently I crashed his NT by doing so. This brought > me a very big question. Was he just bluffing, or the NT seriously cannot > defend against this ? FreeBSD boxes don't crash from this but the net confusion which is the result is not good for anyone. If NT crashes - well, that's exactly what one could suspect:) If you can take two boxes off the net and connect them only to each other, then try all combinations of ifconfig settings on them. It is very informative and do no harm - as long as they are both disconnected from the internet. If you don't have FreeBSD on two boxes, you can boot PicoBSD from a floppy and run it entirely in RAM. I.e. your hard disks won't suffer (unless you mount them yourself etc) /Micke ---------------------------------- Michael Josefsson, MSEE mj@isy.liu.se This message was sent by XFMail running on FreeBSD 3.1 ---------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message