Date: Sat, 13 Oct 2012 23:32:29 -0700 (PDT) From: Doug Hardie <doug@lafn.org> To: FreeBSD-gnats-submit@FreeBSD.org Subject: kern/172683: Duplicate IPv6 Link Local Addresses Message-ID: <201210140632.q9E6WT3G035384@zoon.lafn.org> Resent-Message-ID: <201210140640.q9E6e0Do042952@freefall.freebsd.org>
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>Number: 172683 >Category: kern >Synopsis: Duplicate IPv6 Link Local Addresses >Confidential: no >Severity: critical >Priority: high >Responsible: freebsd-bugs >State: open >Quarter: >Keywords: >Date-Required: >Class: sw-bug >Submitter-Id: current-users >Arrival-Date: Sun Oct 14 06:40:00 UTC 2012 >Closed-Date: >Last-Modified: >Originator: Doug Hardie <bc979@lafn.org> >Release: FreeBSD 9.1-RC2 i386 >Organization: >Environment: System: FreeBSD master.lafn.org 9.1-RC2 FreeBSD 9.1-RC2 #0 r241133: Tue Oct 2 17:11:45 UTC 2012 root@obrian.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC i386 >Description: You can assign identical link local addresses to two different 9.1-RC2 systems on the same LAN and the problem is not detected. When the second machine becomes alive it properly sends a Neighbor Solication with the proper address, but the first machine does not respond to it with a Neighbor Advertisement which would alert the second machine to the duplication and permit it to select a different address. As a result both machines have the same link local address and nothing works. >How-To-Repeat: Determine the link local address the second machine will use and shut it down. On the first machine assign manually that link local address to the appropriate port. Run a tcpdump -ixxx -vx ip6 on the first machine and power up the second. The second machine will send a Neighbor Solication with the duplicated address, but the first machine will not respond to that packet. I have one machine that never sends the original Neighbor Solication for the link local address. It does send for its global addresses. It just starts using the link local address. I can't find any significant differences between those two systems other that the first was a direct install from the CD and the second was a freebsd-update from 9.1-RC1. >Fix: >Release-Note: >Audit-Trail: >Unformatted:
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