arplookup x.x.x.x failed: host is not on local network

Stefan Lambrev stefan.lambrev at
Thu Jul 3 07:48:28 UTC 2008


Peter Jeremy wrote:
> I'm occasionally seeing pairs of messages like the following on
> my NAT host:
> arplookup failed: host is not on local network
> arpresolve: can't allocate route for
Normally this happens in badly configured LAN.

Lets say we have two hosts in the same physical network (same switch for 
Host1 is configured and Hosts2 have

Now when a broadcast or other packet is sent from Host1 it can reach 
Host2 without a problem.
But when Host2 try reach directly Host1 it doesn't know how and from 
here - can't allocate route  ...
I bet have a wrong network mask ;)
> In my particular configuration, there are dual subnets between the NAT
> and target host.  My initial assumption was that the request was
> arriving on the other subnet and I added if_xname to the arplookup
> printf() - but that shows that interface matches the IP address.
> I've looked back through the mailing lists but the previous reports
> of this problem don't match my scenario.
> I've seen this with FreeBSD 5.3, 6.2 and 7.0.
> The (in)frequency of the problem makes me wonder if it's actually a
> resource exhaustion problem.
> Has anyone got any suggestions?


Best Wishes,
Stefan Lambrev
ICQ# 24134177

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