Re: [dnssd] The DNSSD WG has placed draft-sctl-service-registration in state "Call For Adoption By WG Issued"

Toke Høiland-Jørgensen <> Thu, 12 July 2018 20:49 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 09B21130F83 for <>; Thu, 12 Jul 2018 13:49:46 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2
X-Spam-Status: No, score=-2 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id favgIxuhtz0f for <>; Thu, 12 Jul 2018 13:49:44 -0700 (PDT)
Received: from ( []) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id DF13712F1AC for <>; Thu, 12 Jul 2018 13:49:43 -0700 (PDT)
From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= <>
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;; s=20161023; t=1531428578; bh=zM4yAI3qvgPQnUKPCU8hTRPuSfmUV8bl22/OE672B8o=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=Ne+mHtNy2EixkiYakULTZ5nKFUzWiv+A+pcbFSvNFq2WL+F79tk2VrjPKSiPqj6vo 8zYgRD6Yn0gWk1DIZZ7g9g/yBqnAftdsxtu9kfWPEJL3JdRzkHndPruVIQn8cvKO0c 6wn1550wDOXU7CwmtIDLUUYyL44Rezu8lFXL9Neg9i0ZxklXsJF6cTblfLOy6GMMZn ufI9EkHDt8WvMM5AddqK05FDeTTZ3PDvb3SLisMrGCgV0bogprWpEFQYbbrDiktx9A zkQ4TnAtr6RWZbwh6jHWpNWenJ9r8bkd/e66fsUw8/PO6HRsciXPF82h3LSSZiXeJg E9X8836zizw2A==
To: Ted Lemon <>
Cc: David Schinazi <>, dnssd <>
In-Reply-To: <>
References: <> <> <> <> <> <> <> <> <> <> <> <>
Date: Thu, 12 Jul 2018 22:49:30 +0200
X-Clacks-Overhead: GNU Terry Pratchett
Message-ID: <>
MIME-Version: 1.0
Content-Type: text/plain
Archived-At: <>
Subject: Re: [dnssd] The DNSSD WG has placed draft-sctl-service-registration in state "Call For Adoption By WG Issued"
X-Mailman-Version: 2.1.27
Precedence: list
List-Id: "Discussion of extensions to DNS-based service discovery for routed networks." <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Thu, 12 Jul 2018 20:49:46 -0000

Ted Lemon <> writes:

> It seems like the client should just keep maintaining whatever records
> it maintains. If the server doesn't take some updates, then the client
> can just keep trying. Otherwise the client has to somehow model the
> state of the server, which seems unnecessary.

Yeah, agreed.

> As for A and AAAA records, this is an open question: how to handle it.
> Is it a problem to allow a client to update arbitrary A and AAAA
> records? The restriction of only updating the one that corresponds to
> the source address used to send the update is there because we have
> some reasonable assurance that the client actually has that address.
> We could have some hack where we use the neighbor table to notice that
> several addresses are associated with the same layer 2 address, but
> that seems like not what we want to do.

Why is it a problem that a client registers other addresses for its
A(AAA) records? As long as it can't update the addresses of another name
it can't spoof that service; if it sets another device's address as it's
own name, it is just spoofing itself? It could be a problem for PTRs, of
course, but not for A(AAA)?

Maybe this could also be something that is left up to the registration
server as a matter of policy? An example policy could be "only 1 address
per subnet per name" or something... But since a client can just
generate an infinite number of new names, I'm not really sure that buys
much either...

> mDNS seems to just use .arpa. I don't know how/if that works, but I
> definitely don't see how to make it work with the DNS protocol.

Wait, don't see how to make what work with the DNS protocol?