CC: marketing@isc.org MIME-Version: 1.0 X-Spam-Status: No, score=-1.3 required=5.0 tests=BAYES_00,HTML_MESSAGE, HTML_MIME_NO_HTML_TAG,MIME_HTML_ONLY,RP_MATCHES_RCVD,UNPARSEABLE_RELAY autolearn=no version=3.3.1 X-Mailer: PHPMailer 5.2.4 (http://code.google.com/a/apache-extras.org/p/phpmailer/) Content-Type: text/html; charset=UTF-8 Message-ID: <79aa9f84c6cf3945bc2f8fe580781595@www.isc.org> Received: from mx.pao1.isc.org (mx.pao1.isc.org [149.20.64.53]) by bugs.isc.org (Postfix) with ESMTP id 684B82D20051 for ; Fri, 14 Feb 2014 16:30:11 +0000 (UTC) Received: from mx.pao1.isc.org (localhost [127.0.0.1]) by mx.pao1.isc.org (Postfix) with ESMTP id 5E38CC94E0 for ; Fri, 14 Feb 2014 16:29:57 +0000 (UTC) (envelope-from www@iscwebprod.isc.org) Received: from iscwebprod.isc.org (iscwebprod.isc.org [IPv6:2001:4f8:1:d::16]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx.pao1.isc.org (Postfix) with ESMTPS for ; Fri, 14 Feb 2014 16:29:57 +0000 (UTC) (envelope-from www@iscwebprod.isc.org) Received: from www (uid 80) (envelope-from www@iscwebprod.isc.org) id 7b92b5 by iscwebprod.isc.org (DragonFly Mail Agent v0.7); Fri, 14 Feb 2014 16:30:42 +0000 X-DCC-X.dcc-Servers-Metrics: post.isc.org 104; Body=2 Fuz1=2 Fuz2=2 Delivered-To: dhcp-bugs@bugs.isc.org Subject: Bug Submission Form - Version dhcpd 4.2.5 - Error handling overlapping prefix6 leases with different mask lengths Return-Path: X-Original-To: dhcp-bugs@bugs.isc.org X-Priority: 3 Date: Fri, 14 Feb 2014 16:30:42 +0000 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mx.pao1.isc.org To: dhcp-bugs@isc.org Content-Transfer-Encoding: 8bit From: Mark Nejedlo X-RT-Original-Encoding: utf-8 Content-Length: 2162

Bug Report from www.isc.org:

  • Name: Mark Nejedlo
  • Email: mark.nejedlo@tdstelecom.com
  • Software Version: dhcpd 4.2.5
  • OS: RHEL 6.5
  • Subject:Error handling overlapping prefix6 leases with different mask lengths

Bug Detail

While testing various options for how to issue v6 leases, space which had been issueing /64 prefix delegations was changed to issue /56 delegations. This led to dhcpd attempting to issue overlapping leases.

The scenario:

The dhcp server was set up to serve "prefix6 2600:340X:YYY0:0000:: 2600:340X:YYYf:ffff:: /64" for a subnet. The next time a prefix delegation was requested, a lease was issued to the client device for 2600:340X:YYYf:ffff::/64.

Later we decided that we wanted to be able to issue both /56 and /64 leases, so 2600:340X:YYY0::/44 was split in to two prefix statements: "prefix6 2600:340X:YYY0:0000:: 2600:340X:YYY7:ffff:: /64" and "prefix6 2600:340X:YYY8:0000:: 2600:340X:YYYf:ff00:: /56".

So, we have a lease for a /64 in space which is now allocated to /56 assignments. I expected dhcpd to decline the next renewal and issue a new /64 lease out of 2600:340X:YYY0::/45, but instead it continued allowing 2600:340X:YYYf:ffff::/64.

The problem occurred later (after multiple max-lease-time had passed) when a /56 was requested. Despite the existing valid lease for 2600:340X:YYYf:ffff::/64, a lease was issued for 2600:340X:YYYf:ff00::/56, which the router promptly refused due to the new /56 delegation conflicting with the old, but valid, /64 delegation.

I'm currently running 4.2.5. I see that 4.2.6 and 4.3.0 came out earlier this month, but I have not yet upgraded. I don't see anything in the release notes to make me believe this issue (or anything related to prefix6) has been addressed.

---

This email was received through isc.org Bug Submission Form

All information within this email is considered confidential and for internal use only.