proxy-arp

[Chuck Swiger]

On Aug 13, 2007, at 7:34 AM, Jon Otterholm wrote:
> I have a problem with proxy-arp entries.
>
> If I add an arp-entry:
>
> arp -s $hostip $routermac permanent pub only
>
> the router sends an arp and replies to it's own arp like:
>
> 15:40:02.074419 arp who-has $hostip tell $hostip
> 15:40:02.074663 arp reply $hostip is-at $routermac (oui Unknown)
>
> This is a problem because some clients interpret this as an ip- 
> address conflict.

Are you sure that your router is issuing the ARPOP_REQUESTS?
Is the entry you've published already listed in "arp -a"?

> In my case the router answers for arp on a bridge where all clients  
> have their own member-interface and clients are prohibited to talk  
> directly to each other.
>
> Have I completely misunderstood the proxy-arp function? IMHO the  
> router should only answer to arp for $hostip to other clients than  
> the one that actually have the ip-address.

I use proxy-arp where I've got a router running IPFW which needs to  
forward some IPs on the external/routable subnet to internal RFC-1918  
addresses via NAT.  I don't use the "only" keyword, but do use  
"permanent pub".

-- 
-Chuck