Date: Sun, 14 Oct 2012 23:50:00 GMT From: Doug Hardie <bc979@lafn.org> To: freebsd-net@FreeBSD.org Subject: Re: kern/172683: [ip6] Duplicate IPv6 Link Local Addresses Message-ID: <201210142350.q9ENo0ZT037687@freefall.freebsd.org>
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The following reply was made to PR kern/172683; it has been noted by GNATS. From: Doug Hardie <bc979@lafn.org> To: bug-followup@FreeBSD.org Cc: Subject: Re: kern/172683: [ip6] Duplicate IPv6 Link Local Addresses Date: Sun, 14 Oct 2012 16:42:50 -0700 Here is some more interesting information on the issue. RFC 4862 states = that if the link-local address is MAC based then it should bring down = the link and log the duplicate address error. Kurt Jaeger pointed out = in a private email that there is a sysctl that is supposed to control = this behavior: net.inet6.ip6.dad_count. The value 1 is to permit the = interface to continue to operate and the value 2 is to stop operation. = Sure enough net.inet6.ip6.dad_count =3D 1 as the default value. I = changed it to 2 and ran the tests again. There was no change in the = performance. The interface remained in use and nothing was logged in = /var/log/messages. Unfortunately I no longer have a Vista machine to = test with since it generates non-MAC related link-local addresses. XP = and Win 7 both use MAC based addresses. Using Vista talking to FreeBSD = 7.2, the Neighbor Advertisement was returned by FreeBSD and Vista chose = another link-local address.=
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