Resurrecting "Failed to determine dst MAC address for target"

[RFuentes S <ra.fuentess.sam () gmail com>]

Hello, I'm current working on some NSE scripts with IPv6 and some time ago
  find this error:  " failed to determine dst MAC address for target..."

I was working with VMware and a router cisco 2811 on that time and after
searching on this mailing list  I find was a problem in the past but was
already fixed, so for be sure what was the reason to my problem  I
increased the debuging level and found this extra information:

SENT (2.1690s) neighbor solicitation <IPv6 address of the node using Nmap>
> ff02::1:ff95:9000 who has fe80::219:6ff:fe95:9000

That line is a NDP NEighbor Solicitation to my default gateway, one that my
2811 Cisco Router (IOS 12.4 ) wasnt  answering at all because a wrong
configuration on the nodes with the Vlans (Router was well configured and
nodes got their NDP Router Adverstiment, but the nodes  weren't sending the
multicast and broadcast messages to the correct vlan)  .


But, what have of special this? Well not much, isn't anymore a bug of Nmap
but a odd way to work, all my VM were able to ping remote nodes even with
the wrong configuration of the vlans because  the hosts dind't need to
seend a NDP to the default gateway but seem that  Nmap love to be sure his
gateway is online before to sending anyhting, I'm not sure if that is truly
needed but  can be the reason  people get again that famous error message
and a good signal that the vlans configuration need to be check again.

Hope this help to someone,

-- 
Sincerely, Eng. Raul A. Fuentes Samaniego
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