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IPv6 traffic in LDOM



Hi,

Not sure where this would fit in.

But I had some issues with IPv6 traffic, basically I had no communication other than ICMP. What seems to have solved it for me with was:

# ethtool -K eth0 tx off

I do not have this issue on the squeeze and wheezy installations I have running in LDOMs on the same machine. These two seem to have tx cheksumming off by default.

I do see the same behaviour on my gentoo and oracle-linux installations. All of which is running kernel 4.X.

Output from tcpdump. Noticeable difference seems to be the bad udp cksum.

tx-checksumming: on
02:01:26.551180 AF IPv6 (28), length 100: (flowlabel 0xa7ea2, hlim 56, next-header UDP (17) payload length: 56) 2001:16d8:ffc0:0:214:4fff:fef8:82be.123 > 2001:16d8:eecb:0:21e:6ff:fec1:32a4.123: [bad udp cksum 0xc4a7 -> 0xd081!] NTPv4, length 48
Client, Leap indicator: clock unsynchronized (192), Stratum 0 (unspecified), poll 3 (8s), precision -6
Root Delay: 1.000000, Root dispersion: 1.000000, Reference-ID: (unspec)
 Reference Timestamp:  0.000000000
 Originator Timestamp: 0.000000000
 Receive Timestamp:    0.000000000
 Transmit Timestamp:   3670358486.507984519 (2016/04/23 02:01:26)
   Originator - Receive Timestamp:  0.000000000
   Originator - Transmit Timestamp: 3670358486.507984519 (2016/04/23 02:01:26)

tx-checksumming: off
02:03:04.732493 AF IPv6 (28), length 100: (flowlabel 0xa7ea2, hlim 56, next-header UDP (17) payload length: 56) 2001:16d8:ffc0:0:214:4fff:fef8:82be.123 > 2001:16d8:eecb:0:21e:6ff:fec1:32a4.123: [udp sum ok] NTPv4, length 48
Client, Leap indicator: clock unsynchronized (192), Stratum 0 (unspecified), poll 3 (8s), precision -6
Root Delay: 1.000000, Root dispersion: 1.000000, Reference-ID: (unspec)
 Reference Timestamp:  0.000000000
 Originator Timestamp: 0.000000000
 Receive Timestamp:    0.000000000
 Transmit Timestamp:   3670358584.688409149 (2016/04/23 02:03:04)
   Originator - Receive Timestamp:  0.000000000
   Originator - Transmit Timestamp: 3670358584.688409149 (2016/04/23 02:03:04)
02:03:04.736695 AF IPv6 (28), length 100: (hlim 63, next-header UDP (17) payload length: 56) 2001:16d8:eecb:0:21e:6ff:fec1:32a4.123 > 2001:16d8:ffc0:0:214:4fff:fef8:82be.123: [udp sum ok] NTPv4, length 48
Server, Leap indicator:  (0), Stratum 1 (primary reference), poll 3 (8s), precision -20
Root Delay: 0.000000, Root dispersion: 0.000289, Reference-ID: GPS^@
 Reference Timestamp:  3670358580.663820624 (2016/04/23 02:03:00)
 Originator Timestamp: 3670358584.688409149 (2016/04/23 02:03:04)
 Receive Timestamp:    3670358584.755725264 (2016/04/23 02:03:04)
 Transmit Timestamp:   3670358584.755841612 (2016/04/23 02:03:04)
   Originator - Receive Timestamp:  +0.067316092
   Originator - Transmit Timestamp: +0.067432411

-kp

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