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[Bug 1584042] Re: IPV6 resolving fails via udp (not tcp) from other server

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Frédéric,

Thank you. This is clear to me now. As it's a driver issue, I'm
reassigning to the kernel package. The kernel team will probably need
more information about your (virtual) hardware and will want you to test
the latest upstream kernel version or similar.

** Summary changed:

- IPV6 resolving fails via udp (not tcp) from other server
+ Hyper-V NIC cannot pass IPv6 UDP packets by default until protocol offload is disabled

** Package changed: bind9 (Ubuntu) => linux (Ubuntu)

** Changed in: linux (Ubuntu)
       Status: Incomplete => New

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https://bugs.launchpad.net/bugs/1584042

Title:
  Hyper-V NIC cannot pass IPv6 UDP packets by default until protocol
  offload is disabled

Status in linux package in Ubuntu:
  New

Bug description:

  Hi,

  On a client server, I can't get a response from a name server in ipv6+udp. On the same server, it works fine in tcp.
  If I log on my name server, I can get a response from himself but, as a client, it can't get a response from another name server.

  here are the steps to reproduce : 
  - Create a new server using Ubuntu server 16.04. Set it to use ipv4 and use your preferred name server. Select absolutely nothing as functionality. 
  - check some nslookup and apt-get stuff to verify network is OK
  - add ipv6 to the interface and refer to an IPV6 nameserver. I have 3 and thats why I noticed the problem >> All 3 ipv6 nameservers are filling the 3 places in resolv.conf.
  - if you don't have 3 ipv6 nameservers, just add one and comment the line with the ipv4 name server.
  - verify your resolv.conf. Should only content ipv6 reference.
  - Now, you can't nslookup anymore... 
  - add some tests : "dig @ipv4server google.com" works but "dig @ipv6server google.com" don't

  
  Here a more tests : 

  
  Nameserver1 : Nameserver1.MyDomain :  XXX.YYY.ZZZ.250 / xxxx:yyyy:zzzz::250
  Client 		StandAloneServer.MyDomain		:   XXX.YYY.ZZZ.209 / xxxx:yyyy:zzzz::209

  With IPV4

  
  # dig @XXX.YYY.ZZZ.226 www.google.fr

  /var/log/named/queries.log on Nameserver1:
  20-May-2016 12:25:02.834 queries: info: client XXX.YYY.ZZZ.209#35116 (www.google.fr): query: www.google.fr IN A +E (XXX.YYY.ZZZ.226)

  Tcp Dump on Nameserver1:
  12:25:02.834092 IP StandAloneServer.MyDomain.35116 > Nameserver1.MyDomain.domain: 62949+ [1au] A? www.google.fr. (42)
  12:25:02.834395 IP Nameserver1.MyDomain.domain > StandAloneServer.MyDomain.35116: 62949 1/4/5 A 216.58.210.195 (204)

  Tcp Dump on Client
  12:25:02.668200 IP StandAloneServer.MyDomain.35116 > Nameserver1.MyDomain.domain: 62949+ [1au] A? www.google.fr. (42)
  12:25:02.669573 IP Nameserver1.MyDomain.domain > StandAloneServer.MyDomain.35116: 62949 1/4/5 A 216.58.210.195 (204)

  
  RESULT:

  ; <<>> DiG 9.10.3-P4-Ubuntu <<>> @XXX.YYY.ZZZ.226 www.google.fr
  ; (1 server found)
  ;; global options: +cmd
  ;; Got answer:
  ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 49591
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 5
  ;; OPT PSEUDOSECTION:
  ; EDNS: version: 0, flags:; udp: 4096
  ;; QUESTION SECTION:
  ;www.google.fr.			IN	A
  ;; ANSWER SECTION:
  www.google.fr.		300	IN	A	216.58.210.195
  ;; AUTHORITY SECTION:
  google.fr.		171625	IN	NS	ns1.google.com.
  [TRUNCATED]



  WITH IPV6
  # dig @xxxx:yyyy:zzzz::226 www.google.fr 

  NOTE  : I only asked once, it created 3 queries with 5 secs
  d’intervalle environ

  /var/log/named/queries.log on Nameserver1:
  20-May-2016 12:32:34.902 queries: info: client xxxx:yyyy:zzzz::209#35362 (www.google.fr): query: www.google.fr IN A +E (xxxx:yyyy:zzzz::226)
  20-May-2016 12:32:39.902 queries: info: client xxxx:yyyy:zzzz::209#35362 (www.google.fr): query: www.google.fr IN A +E (xxxx:yyyy:zzzz::226)
  20-May-2016 12:32:44.902 queries: info: client xxxx:yyyy:zzzz::209#35362 (www.google.fr): query: www.google.fr IN A +E (xxxx:yyyy:zzzz::226)

  Tcp Dump on Nameserver1:
  12:32:34.902598 IP6 StandAloneServer.MyDomain.35362 > Nameserver1.MyDomain.domain: 23393+ [1au] A? www.google.fr. (42)
  12:32:34.902994 IP6 Nameserver1.MyDomain.domain > StandAloneServer.MyDomain.35362: 23393 1/4/5 A 216.58.210.195 (204)
  …
  12:32:39.902644 IP6 StandAloneServer.MyDomain.35362 > Nameserver1.MyDomain.domain: 23393+ [1au] A? www.google.fr. (42)
  12:32:39.902975 IP6 Nameserver1.MyDomain.domain > StandAloneServer.MyDomain.35362: 23393 1/4/5 A 216.58.210.195 (204)
  …
  12:32:39.902644 IP6 StandAloneServer.MyDomain.35362 > Nameserver1.MyDomain.domain: 23393+ [1au] A? www.google.fr. (42)
  12:32:39.902975 IP6 Nameserver1.MyDomain.domain > StandAloneServer.MyDomain.35362: 23393 1/4/5 A 216.58.210.195 (204)

  
  Tcp Dump on Client12:32:34.725312 IP6 StandAloneServer.MyDomain.35362 > Nameserver1.MyDomain.domain: 23393+ [1au] A? www.google.fr. (42)
  12:32:34.726036 IP6 Nameserver1.MyDomain.domain > StandAloneServer.MyDomain.35362: 23393 1/4/5 A 216.58.210.195 (204)
  …
  12:32:39.725199 IP6 StandAloneServer.MyDomain.35362 > Nameserver1.MyDomain.domain: 23393+ [1au] A? www.google.fr. (42)
  12:32:39.726045 IP6 Nameserver1.MyDomain.domain > StandAloneServer.MyDomain.35362: 23393 1/4/5 A 216.58.210.195 (204)
  …
  12:32:44.725288 IP6 StandAloneServer.MyDomain.35362 > Nameserver1.MyDomain.domain: 23393+ [1au] A? www.google.fr. (42)
  12:32:44.725944 IP6 Nameserver1.MyDomain.domain > StandAloneServer.MyDomain.35362: 23393 1/4/5 A 216.58.210.195 (204)

  
  RESULT

  
  ; <<>> DiG 9.10.3-P4-Ubuntu <<>> @xxxx:yyyy:zzzz::226 www.google.fr
  ; (1 server found)
  ;; global options: +cmd
  ;; connection timed out; no servers could be reached

  
  but, if I do the same query with the tcp flag, all is OK : 

  
  # dig +tcp @xxxx:yyyy:zzzz::226 www.google.fr 

  ; <<>> DiG 9.10.3-P4-Ubuntu <<>> +tcp xxxx:yyyy:zzzz::226 www.google.fr
  ; (1 server found)
  ;; global options: +cmd
  ;; Got answer:
  ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 41105
  ;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 4, ADDITIONAL: 5

  ;; OPT PSEUDOSECTION:
  ; EDNS: version: 0, flags:; udp: 4096
  ;; QUESTION SECTION:
  ;www.google.fr.			IN	A

  ;; ANSWER SECTION:
  www.google.fr.		300	IN	A	216.58.210.195

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