[Nottingham] NIC MACs aliases & IP aliases

Martin martin at ml1.co.uk
Wed May 27 17:09:18 UTC 2009

Martin wrote:
> [---]
>>> Is there a "arp & ping response" utility that I can attach to a tap to try?
>> arping :)
> Yes but the wrong way around! :-/
> A tap receives an external arping packet ok (as shown using tcpdump). 
> Then does nothing with it.
> So, when using arping on some remote host to the local host with the 
> taps, what can I hang onto the tap on the local host to listen for an 
> arping and send an arping reply back? :-)

Anyone got some code or any pointers that I can plug in to the multimac 
code to generate arp responses and also ICMP ping echos?

A bit of surfing so far suggests that the arp and ping code is 
abstracted in the kernel and can be called up if I make my own psuedo 
driver for an interface... Anything like that already available?

tap + arp + ping?

Or is there no problem to having a src IP + src MAC_tap pair that is 
different to the return dst IP + dst MAC_eth pair? (That indeed doesn't 
seem to matter on my network. All that seems to be required is for the 
arp-who-has to pick up the dst MAC_eth.)



Martin Lomas
martin at ml1.co.uk

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