From owner-freebsd-virtualization@freebsd.org Tue Jul 7 13:09:12 2015 Return-Path: Delivered-To: freebsd-virtualization@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2154B995C46; Tue, 7 Jul 2015 13:09:12 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98]) (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 D18C71E82; Tue, 7 Jul 2015 13:09:11 +0000 (UTC) (envelope-from slw@zxy.spb.ru) Received: from slw by zxy.spb.ru with local (Exim 4.84 (FreeBSD)) (envelope-from ) id 1ZCScQ-000Aoo-Rw; Tue, 07 Jul 2015 16:09:02 +0300 Date: Tue, 7 Jul 2015 16:09:02 +0300 From: Slawa Olhovchenkov To: Pavel Timofeev Cc: freebsd-current@freebsd.org, "freebsd-virtualization@freebsd.org" Subject: Re: MS DNS doesn't answer to CURRENT under Hyper-V Message-ID: <20150707130902.GA41189@zxy.spb.ru> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: slw@zxy.spb.ru X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 07 Jul 2015 13:09:12 -0000 On Tue, Jul 07, 2015 at 02:50:49PM +0300, Pavel Timofeev wrote: > Hi! > I have a test virtual machine which runs CURRENT under Hyper-V. It's > amd64 r285198 now. > It can't get any response from MS DNS server. Well, it could two or > three weeks ago, but after upgrade it's not able to do it anymore. > Google DNS answers without problems meanwhile (sic!). > > What I do: > # host google.ru 192.168.25.3 > I see that MS DNS (192.168.25.3) server receives these packets, but > ignores them. > And no matter how my system asks MS DNS. Every daemon can't get response too. > > I know that nothing was changed in MS DNS server. No doubt. > Then I tried different available CURRENT snapshot ISOs. > > FreeBSD-11.0-CURRENT-amd64-20150630-r284969-disc1.iso - MS DNS does not answer. > > FreeBSD-11.0-CURRENT-amd64-20150625-r284814-disc1.iso - MS DNS does not answer. > > FreeBSD-11.0-CURRENT-amd64-20150618-r284544-disc1.iso - MS DNS answers! > > So something was committed to CURRENT between 20150618 and 20150625. > This something ruins communication with MS DNS. > > Then I tried latest > FreeBSD-11.0-CURRENT-amd64-20150630-r284969-disc1.iso on bare metal - > MS DNS answered! > > Looks like that something is related to Hyper-V code. > > Maybe it changes packets somehow? I can gather and provide more info > (tcpdump?) if you ask, it's not a problem! Author: whu Date: Wed Jun 24 06:01:29 2015 New Revision: 284746 URL: https://svnweb.freebsd.org/changeset/base/284746 Log: TSO and checksum offloading support for Netvsc driver on Hyper-V. ===== Try tcpdump/wireshark on FreeBSD and MS DNS host. Check validating IP/UDP checksums. Try off checksum offloading on network interface (ifconfig ifname -txcsum -rxcsum)