On 1/25/06, Lee Sharp <leesharp at hal dash pc dot org> wrote:
>
> You see, all OS's have a local DNS cache.  They request a lookup.  The
> m0n0wall forwards the lookup.  It times out.  The m0n0 responds with a
> "lookup failed" and the local OS caches that fail.  If you flush the cache,
> or force a new lookup, it will try again.
>

I believe dnsmasq (m0n0wall's caching DNS server) will probably also
cache those lookup failures, so then it would affect everything on
your network.


> However, I think the root cause is the
> errors.
>

I would agree.


> > Aren't the collisions just due to it being a half-duplex wireless
> > connection?
>

Collisions, yes, errors, no.  The percentage of collisions is
reasonable.  The percentage of errors is definitely not.

Keep in mind that DNS is UDP, so if an error causes a DNS packet to be
lost, you're outta luck.  TCP will still function pretty much normally
with ~1% loss.  It will have a measurable effect on TCP performance,
but one that could go unnoticed unless you're actually measuring.

-Chris