Hi,
I think both ipv6 addresses are local scope at netapp target (fe80::2a0:98ff:fe0a:1d59) and esx inititator (fe80::250:56ff:fe7e:c5d6) side.
This local scope addresses would have problem connecting with tcp/ip without giving a outbound interface, which by default esx sw iscsi would not give.
Netapp side might not be able to route iscsi packets either, if they don't suuport local scope ipv6 initiators, which I'm not sure.
(BTW, this does not explain why you can't vmkping from esx to netapp, but it can be the cause of failure of discovery and login iscsi targets)
So can you try to config. global scope ipv6 address at both ends?
Regards,
- Kun