Date: Mon, 13 Jul 2015 08:06:01 +0000 From: Wei Hu <weh@microsoft.com> To: Pavel Timofeev <timp87@gmail.com>, Slawa Olhovchenkov <slw@zxy.spb.ru> Cc: "freebsd-current@freebsd.org" <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: <BY1PR03MB1434AB3E1C8F2D66BDE1AB2CBB9C0@BY1PR03MB1434.namprd03.prod.outlook.com> In-Reply-To: <CAAoTqft_u1YEOGf6pThhHd-JuYoGnxzQxFpo-57SCUJ0OksWGw@mail.gmail.com> References: <CAAoTqftvtQunx%2BWCL4%2BBz-mYSgqCTcGx1aAyemfaz%2B=0ogZuWw@mail.gmail.com> <20150707130902.GA41189@zxy.spb.ru> <CAAoTqfsUfdAP1G=U4eDg3hfmuHtoosgGjOd9gMrehX%2BrcxaiJw@mail.gmail.com> <20150707154906.GA44094@zxy.spb.ru> <CAAoTqft_u1YEOGf6pThhHd-JuYoGnxzQxFpo-57SCUJ0OksWGw@mail.gmail.com>
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We have root caused the problem. This issue happens on the Hyper-Vs on Wind= ows Server 2012 (Win 8.0) and earlier releases. On these releases, the UPD = checksum offloading on host side does not work properly. The workaround is = to disable UPD checksum offloading in the FreeBSD guest through 'ifconfig'.= We are also working on a patch to turn off UPD checksum offloading in the = netvsc driver when detecting the Hyper-V releases.=20 The UDP checksum offloading works fine on Windows Server 2012R2 and Win 8.1= hosts.=20 Thanks Pavel and Slawa for the support. Wei > -----Original Message----- > From: owner-freebsd-virtualization@freebsd.org [mailto:owner-freebsd- > virtualization@freebsd.org] On Behalf Of Pavel Timofeev > Sent: Wednesday, July 8, 2015 4:06 PM > To: Slawa Olhovchenkov > Cc: freebsd-current@freebsd.org; freebsd-virtualization@freebsd.org > Subject: Re: MS DNS doesn't answer to CURRENT under Hyper-V >=20 > Ok, r284746 is the root of the problem. MS DNS works under r284745 and > doesn't work under r284746. > Slawa, what should I look at in wireshark output? >=20 >=20 > 2015-07-07 18:49 GMT+03:00 Slawa Olhovchenkov <slw@zxy.spb.ru>: > > On Tue, Jul 07, 2015 at 06:04:46PM +0300, Pavel Timofeev wrote: > > > >> Well, turning off checksum offloading by `ifconfig hn0 -txcsum > >> -rxcsum` definitely helps. > >> > >> As for tcpdump I'm not completely sure if I did it right, but I see > >> "bad udp cksum" phrase: > >> > >> # tcpdump -i hn0 -vvv -nn udp dst port 53 > >> tcpdump: listening on hn0, link-type EN10MB (Ethernet), capture size > >> 262144 bytes > >> 18:01:19.139994 IP (tos 0x0, ttl 64, id 61218, offset 0, flags > >> [none], proto UDP (17), length 51) > >> 192.168.25.26.45683 > 192.168.25.3.53: [bad udp cksum 0xb39e -> > >> 0xf210!] 52886+ A? ya.ru. (23) > >> 18:01:24.140544 IP (tos 0x0, ttl 64, id 17293, offset 0, flags > >> [none], proto UDP (17), length 51) > >> 192.168.25.26.12575 > 192.168.25.3.53: [bad udp cksum 0xb39e -> > >> 0x7365!] 52886+ A? ya.ru. (23) > > > > tcpdump "bad udp cksum" is normal on FreeBSD host in case checksum > > offload (and may be need only for help finding issuse in code). Need > > wireshark capturing from MS DNS host (or from mirroring port). > _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to "freebsd-virtualization- > unsubscribe@freebsd.org"
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