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Re: This (new to me) ip thingy




	Hi.

On Tue, Oct 03, 2017 at 04:36:12AM -0400, Gene Heskett wrote:

> > > >Frankly I'm not surprised that it failed to resolve 224.0.0.251.
> > > > Nobody sane would add a DNS record for this anyway.
> > >
> > > I think thats from avahi, is definitely is not anything I have
> > > configured.
> >
> > Multicasts are not anything that *anyone* should configure.
> > The whole idea of them is that your L2 network segment configures by
> > itself.
>
> In that class A?

Classful networks are obsolete. See RFC 4632.

> Not even my isp has anything there.

Mutlicasts are limited to a *local* network segment. Unless a black
magic called IGMP proxy is involved.

> Its not a pingable address from here as I believe dd-wrt would stop it, nor does whois have a clue.

Of course it's not pingable.
The whole point of 224.0.0.0/4 network is that there is no host that has
such addresses assigned, yet UDP packets should come to any host in a
*local* (in L2 sense) network segment. Assuming that said host wants to
listen such multicast address.

Also, RFC 1112.

> NSA back door?  Damnifiknow.

Nope. There's no point in such backdoor as multicasts are not routable.

> Traceroute gets zero response too.  

It should. Multicasts don't use ICMP.

Reco