DUPlicate icmpv6 echo replies over wi0

[Greg Troxel]

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 at ir.bbn.com>