Windows 2016 iSCSI initiator & FreeNAS iSCSI target woes

[xyzzy]

I have three physical boxes:
1) FreeNAS 11.0 U3
2) ESXi 6.5
3) Windows Server 2016

All are beefy server-class boxes with 64GB of RAM.

Each of the boxes has an X710-DA4 10G NIC.
Boxes 1 & 2 are directly connected via SFP+ DAC and use the 192.168.20.x subnet exclusively and can ping each other.
Boxes 1 & 3 are directly connected via SFP+ DAC and use the 192.168.21.x subnet exclusively and can ping each other.

I have two iSCSI targets on the FreeNAS box that are working flawlessly from VMware.

However, I can't figure out how to get Windows Server 2016 to mount the targets. The targets appear in the "iSCSI Initiator Properties" window with a status of "Conencted". But, if I try to disconnect one, the "iSCSI Initiator Properties" completely hangs.

Also, I see the following error message on the FreeNAS box every 66 seconds:

Code:

WARNING: 192.168.21.3 (iqn.1991-05.com.microsoft:win2016.mydomain.net): no ping reply (NOP-Out) after 5 seconds; dropping connection

FWIW, I've been doing all of this testing with the VMware box turned off.

What am I doing wrong?

 

[xyzzy]

I figured it out. I'm using jumbo frames on my 10G connections. I had previously set the MTU to 9000 on the Windows and FreeNAS sides. What I didn't realize was that I also had to go into the Intel NIC driver properties for the port in question, go to the Advanced tab and change the Jumbo Packet setting from "Disabled" to "9014 Bytes".