Comment 20 for bug 1584042

On "client" and "server":
Setting up linux-headers-4.6.0-040600 (4.6.0-040600.201605151930) ...
Setting up linux-headers-4.6.0-040600-generic (4.6.0-040600.201605151930) ...
Setting up linux-image-4.6.0-040600-generic (4.6.0-040600.201605151930) ...

root@Server:/# uname -a
Linux Server 4.6.0-040600-generic #201605151930 SMP Sun May 15 23:32:59 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

root@Client:/# uname -a
Linux Client 4.6.0-040600-generic #201605151930 SMP Sun May 15 23:32:59 UTC 2016 x86_64 x86_64 x86_64 GNU/Linux

root@Client:/# ethtool --show-offload eth0
Features for eth0:
rx-checksumming: on
tx-checksumming: on
 tx-checksum-ipv4: off [fixed]
 tx-checksum-ip-generic: on
 tx-checksum-ipv6: off [fixed]
 tx-checksum-fcoe-crc: off [fixed]
 tx-checksum-sctp: off [fixed]

root@Client:/# ethtool --offload eth0 rx off tx off
Actual changes:
rx-checksumming: off
tx-checksumming: off

root@Server:/# ethtool --offload eth0 rx off tx off
Actual changes:
rx-checksumming: off
tx-checksumming: off

oot@Client:/# dig @2001:660:660c:120::2000 testubuntu NS

; <<>> DiG 9.10.3-P4-Ubuntu <<>> @2001:660:660c:120::2000 testubuntu NS
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 2664
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 2

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;testubuntu. IN NS

;; ANSWER SECTION:
testubuntu. 172800 IN NS server.testubuntu.

--------------------------------------
Bug still present upstream !!
Confirmed
tag: kernel-bug-exists-upstream