[ale] can anyone provide a thumbnail sketch of how arp is supposed to work ?

[Joseph A Knapka]

Courtney Thomas wrote:
> 
> Thank you for staying with me on this.

No problem. I'm adding ALE back in so someone else can jump
in if I tell you something really stupid :-)

> First off I have about 12 hosts on 2 different hubs and there's a switch
> linked but no hosts on it yet.
> 
> I'm using dialup to the ISP with Freebsd doing NAT. Freebsd is on 1 hub
> and debian the other, but they are both on the same logical subnet.
> 
> Both the Freebsd and Debian boxes have public IP addresses.
> 
> One further thing I noticed when using tcpdump. I noticed that when
> broadcasting was occurring that one host that was powered off, caused
> the router [Freebsd] to go out on the web looking for it.

Two things:

(1) No ARP traffic should go across a dialup link. The
dialup server does proxy-ARP for your FreeBSD machine,
but none of that traffic should ever appear on the
dialup link itself.

(2) How do you know the router is "going out to the web"?
You are presumably running tcpdump on a host on your
LAN; that cannot tell you anything about traffic
across the link to your ISP.

> Does this mean
> that I have to have any powered off hosts commented out of /etc/hosts to
> prevent this behavior, or that the Router is misconfigured, or what ?

None of the above, I suspect this is just a problem
with interpreting tcpdump output.

If the problem is that your router is dialing your
ISP when you don't expect it to, that is almost
certain to be a DNS issue.

-- 
  Using open-source software: free.
  Pissing Bill Gates off: priceless.

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