Issues gatewaying through Hyper-V

[Larry Baird]

I have two identical setups on Hyper-V 2012R2 and Hype-V windows 10.

I have two FreeBSD 10.2-RELEASE-p6 Hyper-V hosts in both cases.
The first FreeBSD host (client) has one NIC configured to use a Private
network. The second (gateway) has two nics. One private and one external. 
The gateway box has the gateway_enable option set to YES in its rc.conf.
The boxes otherwize of very vanilla. 

I get failures forwarding thru gateway on both versions of Hyper-V. But
they fail in different ways.

On both configurations, I can ping thru the gateway from the client to reach
the internet.  

For the 2012r2 configuration I can do DNS looks. The command
"host www.google.com 8.8.8.8" works on the client.

For the Windows 10 configuration the "host" command fails.

For the 2012r2, "curl http://www.goggle.com" times out on client.

Under Windows 10, I can successfuly do curl requests by IP address.

Using tcpdump on the client for the failure cases, I see bad checksums
in the responses retunred to the failing commands. I tried turning off
rxcsum, txcsum, tso4 and tso6 on all interfaces. This did not effect the
results. 

Using tcpdup on the gateway on either interface shows valid checksums.
They are getting corrupted after they leave FreeBSD on their way to the
client. I assume this means this is an internal HyperV issue. I wonder if
there anything the FreeBSD hn(4) driver can do? 

Anybody else seeing this issue? 

Larry

-- 
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Larry Baird
Global Technology Associates, Inc. 1992-2012 	| http://www.gta.com
Celebrating Twenty Years of Software Innovation | Orlando, FL
Email: lab at gta.com                 		| TEL 407-380-0220