Re: [dhcwg] Minimum length for inbound DHCP packets
Tobin Coziahr <tobin.coziahr@sun.com> Tue, 05 March 2002 22:43 UTC
Received: from optimus.ietf.org (ietf.org [132.151.1.19] (may be forged)) by ietf.org (8.9.1a/8.9.1a) with ESMTP id RAA03931 for <dhcwg-archive@odin.ietf.org>; Tue, 5 Mar 2002 17:43:03 -0500 (EST)
Received: (from daemon@localhost) by optimus.ietf.org (8.9.1a/8.9.1) id RAA10708 for dhcwg-archive@odin.ietf.org; Tue, 5 Mar 2002 17:43:05 -0500 (EST)
Received: from optimus.ietf.org (localhost [127.0.0.1]) by optimus.ietf.org (8.9.1a/8.9.1) with ESMTP id RAA10175; Tue, 5 Mar 2002 17:37:30 -0500 (EST)
Received: from ietf.org (odin [132.151.1.176]) by optimus.ietf.org (8.9.1a/8.9.1) with ESMTP id RAA05318 for <dhcwg@optimus.ietf.org>; Mon, 4 Mar 2002 17:26:54 -0500 (EST)
Received: from mail.bucknell.edu (marge.bucknell.edu [134.82.9.1]) by ietf.org (8.9.1a/8.9.1a) with ESMTP id RAA27803 for <dhcwg@ietf.org>; Mon, 4 Mar 2002 17:26:50 -0500 (EST)
Received: from kathmandu.sun.com (kathmandu.sun.com [192.18.98.36]) by mail.bucknell.edu (8.11.6/8.11.6) with ESMTP id g24MQr213376 for <dhcp-v4@bucknell.edu>; Mon, 4 Mar 2002 17:26:53 -0500 (EST)
Received: from sunmail1.Sun.COM ([129.145.1.2]) by kathmandu.sun.com (8.9.3+Sun/8.9.3) with ESMTP id PAA15207; Mon, 4 Mar 2002 15:26:51 -0700 (MST)
Received: from jurassic.eng.sun.com (jurassic.Eng.Sun.COM [129.146.84.45]) by sunmail1.Sun.COM (8.9.3+Sun/8.9.3/ENSMAIL,v2.1p1-Sun.COM.mod.2) with ESMTP id OAA23557; Mon, 4 Mar 2002 14:26:55 -0800 (PST)
Received: from sun.com (raistlin.Eng.Sun.COM [129.146.86.244]) by jurassic.eng.sun.com (8.12.2+Sun/8.12.2) with ESMTP id g24MQnsu964715; Mon, 4 Mar 2002 14:26:49 -0800 (PST)
Message-ID: <3C83F4BE.6D303929@sun.com>
Date: Mon, 04 Mar 2002 14:27:10 -0800
From: Tobin Coziahr <tobin.coziahr@sun.com>
Organization: Sun Microsystems
X-Mailer: Mozilla 4.76 [en] (X11; U; SunOS 5.9 sun4u)
X-Accept-Language: en
MIME-Version: 1.0
To: Greg Kilfoyle <gregk@redback.com>
CC: dhcp-v4@bucknell.edu
Subject: Re: [dhcwg] Minimum length for inbound DHCP packets
References: <1015273324.19876.61.camel@wan-pppoe-1.lab.redback.com>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Content-Transfer-Encoding: 7bit
Sender: dhcwg-admin@ietf.org
Errors-To: dhcwg-admin@ietf.org
X-Mailman-Version: 1.0
Precedence: bulk
List-Id: <dhcwg.ietf.org>
X-BeenThere: dhcwg@ietf.org
Content-Transfer-Encoding: 7bit
Greg- The generally accepted minimum length that I've seen in use is 240 bytes. This is the bare minimum, the basic fields and the magic cookie. I actually had to update a server recently that was dropping packets under 300 bytes, too. Clients are more frequently using packets under the BOOTP minimum size (Which is perfectly legal under RFC 2131). -Tobin Greg Kilfoyle wrote: > > Hi, > > For a DHCP server or relay agent, I was wondering what is a reasonable > minimum length to check for on inbound packets. This is for DHCP support > only, no BOOTP support. > > I was thinking an initial check should use the BOOTP minimum length and > check for a DHCP packet length of 300 bytes (which makes 328 bytes > including normal IP and UDP headers). > > Using a test tool to test the DHCP server implementation showed that the > test tool was sending DHCP packets of less than 300 bytes (and the above > check was failing). > > On one hand this is a problem with the test tool; on the other hand, how > many clients out there do not send the minimum BOOTP length? In other > words, if I don't allow less then the BOOTP minimum length, how many > clients will not work correctly? > > Maybe a more forgiving approach would be a length that includes the > magic cookie and at least one option (an end option being 1 byte). > > Any thoughts welcome. > > Thanks, Greg. > -- > Greg Kilfoyle (gregk@redback.com) > > _______________________________________________ > dhcwg mailing list > dhcwg@ietf.org > https://www1.ietf.org/mailman/listinfo/dhcwg -- Tobin Coziahr 650-786-7118 (x87118) Solaris Networking tobin.coziahr@sun.com Sun Microsystems _______________________________________________ dhcwg mailing list dhcwg@ietf.org https://www1.ietf.org/mailman/listinfo/dhcwg
- [dhcwg] Minimum length for inbound DHCP packets Greg Kilfoyle
- Re: [dhcwg] Minimum length for inbound DHCP packeā¦ Tobin Coziahr