From owner-freebsd-questions Sun Mar 25 17:36: 3 2001 Delivered-To: freebsd-questions@freebsd.org Received: from mailhost01.reflexnet.net (mailhost01.reflexnet.net [64.6.192.82]) by hub.freebsd.org (Postfix) with ESMTP id 356F737B718 for ; Sun, 25 Mar 2001 17:35:58 -0800 (PST) (envelope-from cjc@rfx-216-196-73-168.users.reflexcom.com) Received: from rfx-216-196-73-168.users.reflexcom.com ([216.196.73.168]) by mailhost01.reflexnet.net with Microsoft SMTPSVC(5.5.1877.197.19); Sun, 25 Mar 2001 17:33:46 -0800 Received: (from cjc@localhost) by rfx-216-196-73-168.users.reflexcom.com (8.11.3/8.11.1) id f2Q1ZnE10914; Sun, 25 Mar 2001 17:35:49 -0800 (PST) (envelope-from cjc) Date: Sun, 25 Mar 2001 17:35:49 -0800 From: "Crist J. Clark" To: Jim Freeze Cc: cjclark@alum.mit.edu, "Andrew C. Hornback" , FreeBSD Questions Subject: Re: Meaging of Security Check? Message-ID: <20010325173549.E5425@rfx-216-196-73-168.users.reflex> Reply-To: cjclark@alum.mit.edu References: <20010325151642.C5425@rfx-216-196-73-168.users.reflex> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: ; from jim@freeze.org on Sun, Mar 25, 2001 at 07:55:32PM -0500 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sun, Mar 25, 2001 at 07:55:32PM -0500, Jim Freeze wrote: > On Sun, 25 Mar 2001, Crist J. Clark wrote: > > > On Sat, Mar 24, 2001 at 11:43:32AM -0500, Andrew C. Hornback wrote: > > > > -----Original Message----- > > > > From: owner-freebsd-questions@FreeBSD.ORG > > > > [mailto:owner-freebsd-questions@FreeBSD.ORG]On Behalf Of Jim Freeze > > > > Sent: Saturday, March 24, 2001 7:50 AM > > > > To: questions@freebsd.org > > > > Subject: Meaging of Security Check? > > > > > > > > > > > > Hi: > > > > > > > > I received the following security check and was wondering what it means: > > > > > > > > eeyore1 security check output > > > > > > > > eeyore1 kernel log messages: > > > > > x3f8-0x3ff irq 4 flags 0x10 on isa > > > > > ipfw: 40 Accept TCP 157.95.47.65:776 24.9.218.175:22 in via vx0 > > > > > ipfw: 65000 Deny UDP 24.9.218.175:68 24.2.7.70:67 out via vx0 > > > > > ipfw: 65000 Deny UDP 24.9.218.175:68 24.2.7.70:67 out via vx0 > > > > > ...where the above is repeated for about 100 lines > > > > > > > > I looked up port 67 in /etc/services and it says: > > > > > > > > bootps 67/tcp dhcps #Bootstrap Protocol Server > > > > bootps 67/udp dhcps #Bootstrap Protocol Server > > > > > > > > nslookup says: > > > > > > > > % nslookup 24.2.7.70 > > > > Server: proxy1.lxintn1.ky.home.com > > > > Address: 24.5.116.15 > > > > > > > > Name: lh1.rdc1.tn.home.com > > > > Address: 24.2.7.70 > > > > > > > > Can someone explain what is happening here? > > > > > > To my (semi)trained eye... you're subject to a new form of a DoS attack. > > > > [snip] > > > > Guys, guys. You're hurting me. > > > > It looks like Jim has broken his own DHCP setup. 24.9.218.175 looks > > like the address of the machine generating these logs, correct? It is > > blocking its own outgoing packets to lh1.rdc1.tn.home.com which is > > your DHCP server, right? > > Hmmm.. My dns machines are 24.5.116.15 and 24.5.116.17. My ip has not > changed (thankfully) and is still 24.9.218.175. DNS does not really have anything to do with this. Check, $ grep dhcp-server /var/db/dhclient.leases To see who your server is. You may also want to examine that file to see how far expired your lease is. > > Your machine is trying to renew its lease. You probably want to pass > > that traffic. > > What would the ipfw rule look like? > > ${fwcmd} add pass udp from any to ${dns1} 67 > ${fwcmd} add pass udp from any to ${dns2} 67 ${fwcmd} add pass udp from any 68 to any 67 out via ${oif} ${fwcmd} add pass udp from any 67 to any 68 in via ${oif} Should do it. Again, your DNS servers don't necessarily have anything to do with this. DHCP does not need to know its server's address to work. -- Crist J. Clark cjclark@alum.mit.edu To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message