SLAAC(autoconfig) vs DHCPv6

Darden, Patrick S. darden at armc.org
Tue Aug 19 07:40:36 CDT 2008


1.  I think ARP is effectively a ping for a mac.  It verifies connectivity on level 2 between two hosts.  You have to be on the same segment though....

To make it work, you would have to know the mac address of the remote host, clear the  arp table the local host, then send the ARP request out.

This would still require that each host have IP stacks in place with functioning IP addresses.  Although ARP acts under IP, it still requires IP to function.

2.  I think you might be able to fudge it using RARP, if you just look for signals sent to that address. 

3.  A kind of constant ping might be... if you knew the remote's MAC address you could poison the ARP table with an announcement, spoof the MAC locally, then do MITM stuff and relay communications.

4.  Ok, after all that craziness I did a google search and found ARPING:  http://en.wikipedia.org/wiki/Arping

ARPING still seems to rely upon a proper IP stack and address on both hosts.

Meh, your best bet might be just to scan your arp tables for the mac you are interested in.  I think all NICs broadcast periodically saying "I am here".  Passive ping.
--p

-----Original Message-----
From: Howard C. Berkowitz [mailto:hcb at netcases.net]
Sent: Monday, August 18, 2008 3:42 PM
To: nanog at nanog.org
Subject: RE: SLAAC(autoconfig) vs DHCPv6


This was especially a question when L2 was "in" and routing was out: how do
you ping a MAC address?




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