Problem using file /etc/ethers

Phil Meyer pmeyer at themeyerfarm.com
Mon Jun 8 15:33:35 UTC 2009


On 06/08/2009 06:52 AM, Fau wrote:
> Greetings to anyone,
> i'm trying to reach a NAS that autoconfigure its IP address with DHCP,
> I can't foresee the address because I'm not the dhcp server administrator,
> so I put in /etc/ethers:
> 00:d0:4b:87:4a:ac 192.168.0.111
>
> 192.168.0.111 (is a random address in the same subnet of my pc)
>
> My IP address is 192.168.0.5
> but running ping 192.168.0.111 all the packet are dropped
> smbclient -L 192.168.0.111 return with
> Connection failed (Error NT_STATUS_HOST_UNREACHABLE)
>
> Doing strace ping 192.168.0.111 i can see that /etc/ethers is not read 
> by ping
>
> In /etc/nsswitch.conf there is the line about ethers and is set as
> ethers:    files
>
> Is /etc/ethers deprecated and no program read it?
> Thank you in advance for your help,
> regards,
> Fau


First, there was reverse Arp to obtain an IP.  /etc/ethers and rarpd are 
from those days.

But the Network IS the computer, so along came bootparams and other 
proprietary options built upon the ARP protocol to add additional 
information to the response.

Eventually it pretty much settled down to the DHCP protocol which was 
written to be extensible such that just about anything can be answered 
in the response.  Again, DHCP is an evolution of the original ARP/RARP 
protocol, and it will answer the simplest to the most complex request.

If you have a DHCP server on your network, it then becomes a race 
between your rarpd and their dhcpd to see who will respond first.

However, most network appliances no longer do simple ARP requests.

So to sum it up:

You cannot do what you intend.

Good Luck!




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