Date: Tue, 7 Jul 2015 16:09:02 +0300 From: Slawa Olhovchenkov <slw@zxy.spb.ru> To: Pavel Timofeev <timp87@gmail.com> Cc: freebsd-current@freebsd.org, "freebsd-virtualization@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> In-Reply-To: <CAAoTqftvtQunx%2BWCL4%2BBz-mYSgqCTcGx1aAyemfaz%2B=0ogZuWw@mail.gmail.com> References: <CAAoTqftvtQunx%2BWCL4%2BBz-mYSgqCTcGx1aAyemfaz%2B=0ogZuWw@mail.gmail.com>
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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)
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