From owner-freebsd-net@freebsd.org Fri Nov 29 01:02:35 2019 Return-Path: Delivered-To: freebsd-net@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 4ECB31BE412 for ; Fri, 29 Nov 2019 01:02:35 +0000 (UTC) (envelope-from vas@sibptus.ru) Received: from admin.sibptus.ru (admin.sibptus.ru [IPv6:2001:19f0:5001:21dc::10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 47PGSp0ZnPz4Jfc for ; Fri, 29 Nov 2019 01:02:33 +0000 (UTC) (envelope-from vas@sibptus.ru) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sibptus.ru; s=20181118; h=In-Reply-To:Message-ID:Subject:To:From:Date; bh=9FUYjDTJxxzRHIlDrBPcavWmmYMtI6FCOWeDEV+FtoU=; b=O1rNnSdT5XQNJ4IXvZIOuYC/Tw zpSzpHuSR3iPOHmJB8mO5HGqeNVSUlIG+pZEx08hi8XWDGVrPPNefEAatS8NvJCXAD6pq2GYQ+flA 0jyFxGyKaZWeXj08SfPpjeBuHub/t1VT95EgLTa4PSPSVZJa2S/N97E7JvQI/oUH6was=; Received: from vas by admin.sibptus.ru with local (Exim 4.92.3 (FreeBSD)) (envelope-from ) id 1iaUfy-000HqQ-82 for freebsd-net@freebsd.org; Fri, 29 Nov 2019 08:02:26 +0700 Date: Fri, 29 Nov 2019 08:02:26 +0700 From: Victor Sudakov To: freebsd-net@freebsd.org Subject: Re: Several hosts behind a caching resolver Message-ID: <20191129010226.GA68412@admin.sibptus.ru> References: <20191124123451.GA6593@admin.sibptus.ru> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="y0ulUmNC+osPPQO6" Content-Disposition: inline In-Reply-To: <20191124123451.GA6593@admin.sibptus.ru> X-PGP-Key: http://admin.sibptus.ru/~vas/ X-PGP-Fingerprint: 10E3 1171 1273 E007 C2E9 3532 0DA4 F259 9B5E C634 User-Agent: Mutt/1.12.2 (2019-09-21) X-Rspamd-Queue-Id: 47PGSp0ZnPz4Jfc X-Spamd-Bar: -------- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=sibptus.ru header.s=20181118 header.b=O1rNnSdT; dmarc=pass (policy=none) header.from=sibptus.ru; spf=pass (mx1.freebsd.org: domain of vas@sibptus.ru designates 2001:19f0:5001:21dc::10 as permitted sender) smtp.mailfrom=vas@sibptus.ru X-Spamd-Result: default: False [-8.42 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; R_DKIM_ALLOW(-0.20)[sibptus.ru:s=20181118]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+mx]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.20)[multipart/signed,text/plain]; TO_DN_NONE(0.00)[]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; RCPT_COUNT_ONE(0.00)[1]; IP_SCORE(-3.32)[ip: (-9.86), ipnet: 2001:19f0:5000::/38(-4.93), asn: 20473(-1.76), country: US(-0.05)]; DKIM_TRACE(0.00)[sibptus.ru:+]; DMARC_POLICY_ALLOW(-0.50)[sibptus.ru,none]; SIGNED_PGP(-2.00)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+,1:+,2:~]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:20473, ipnet:2001:19f0:5000::/38, country:US]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Nov 2019 01:02:35 -0000 --y0ulUmNC+osPPQO6 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Any more opinions please if DNS queries leak information about the internal network topology and size to the resolver? It would be interesting to consider 2 separate cases: 1. The internal network is NATed. 2. The internal network is IPv6 with ipv6_privacy=3D"YES" Victor Sudakov wrote: > Dear Colleagues, >=20 > Several hosts of the local network use a FreeBSD server with BIND or > local-unbound as a caching resolver. Let's call it "Resolver A." > Resolver A forwards all queries to another resolver, e.g. 8.8.8.8 or > some other, let's call it "Resolver B." >=20 > Can the operator of Resolver B figure out how many clients there are > behind Resolver A, or obtain any other information about the hosts on > the said local network (like their operating system etc)? In other > words, does Resolver A effectively anonymize the queries, or is some > information about the internal network leaking? >=20 > --=20 > Victor Sudakov, VAS4-RIPE, VAS47-RIPN > 2:5005/49@fidonet http://vas.tomsk.ru/ --=20 Victor Sudakov, VAS4-RIPE, VAS47-RIPN 2:5005/49@fidonet http://vas.tomsk.ru/ --y0ulUmNC+osPPQO6 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJd4G4iAAoJEA2k8lmbXsY0aD0H/0BTJQ8EbfK9n0PJBbg7EevI jXKkeuippeCEqXXH5CKAKA+2uaDbGx8fCya3vpDHlxPFA2LPcWM51Cg3V9cH8Ews tMZgzj0pRInKT6jzr8j/HpewtYXayc4JRFqLEweVEFlU+uTcni/tTEQw4HdOFS+u ztS+XhhqAmrNf3L5IpsUZ4XGEPGRm0WRL/OgSKVRWknP8vsJzvGfXA4I7cqMTtTJ /Jg7l3lgD6O8olIEJzA8pbtmuHz+TJm8Ke341vtzSxFSEyY42zlkZefJCakl4eLv 53NjLqc6jEPgu9boMGxjC40Mssspbn+coLxjUDzB1YqKdGsGRw9gJ0fMvR9188M= =shfD -----END PGP SIGNATURE----- --y0ulUmNC+osPPQO6--