Date: 05 Sep 2005 09:17:10 -0400 From: Greg Troxel <gdt@ir.bbn.com> To: Folkert Saathoff <folkert@feedface.com> Cc: freebsd-mobile@freebsd.org, snap-users@kame.net Subject: Re: DUPlicate icmpv6 echo replies over wi0 Message-ID: <rmi64tfpsbt.fsf@fnord.ir.bbn.com> In-Reply-To: <49D89F36-BEDB-4FAE-80BE-3F73FA74D773@feedface.com> References: <49D89F36-BEDB-4FAE-80BE-3F73FA74D773@feedface.com>
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The 802.11 mac layer can cause duplicates. If the receiver hears the packet and sends an ack, but the ack is lost, the sender will retransmit, leading to two copies of the packet. In theory a receiver could filter dups, but I haven't noticed code to do this. So I would suggest trying with other traffic and seeing if it is really a ICMPv6-specific problem. Your description makes it sound to me like something other than 802.11 MAC-layer dups are happening, though. I would also suggest tcpdumping on the host behind the router and the hostap machine. -- Greg Troxel <gdt@ir.bbn.com>
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