Dropped packets in Hyper-V VM

[paul_dundee]

Hi All.

I'm running CentOS 7 in Hyper-V Server 2012R2, Gen2 VM. The VM is used solely for openSwan to connect to another site. I consistently see 1% packet loss when pinging across the VPN from client machines. No packets are dropped when pinging across the VPN from the CentOS instance itself. I rebuilt the VM as a Gen1 VM and am experiencing the same issue. I have a 6.5VM with an identical config, Gen1, with no packet loss. As this VPN is currently used for AD and SQL replication, I'd prefer to have as sustainable a connection as possible.

Any help appreciated.

CentOS 6.5 GEN1:
Ping statistics for 172.21.0.4:
Packets: Sent = 3000, Received = 2995, Lost = 5 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 22ms, Maximum = 57ms, Average = 24ms

CentOS 7 GEN2:
Ping statistics for 172.21.0.4:
Packets: Sent = 1000, Received = 988, Lost = 12 (1% loss),
Approximate round trip times in milli-seconds:
Minimum = 22ms, Maximum = 39ms, Average = 23ms

Ping statistics for 172.21.0.4:
Packets: Sent = 3000, Received = 2958, Lost = 42 (1% loss),
Approximate round trip times in milli-seconds:
Minimum = 22ms, Maximum = 54ms, Average = 25ms

Ping statistics for 172.21.0.4:
Packets: Sent = 10000, Received = 9867, Lost = 133 (1% loss),
Approximate round trip times in milli-seconds:
Minimum = 22ms, Maximum = 74ms, Average = 24ms

CentOS 7 GEN1:
Ping statistics for 172.21.0.4:
Packets: Sent = 1000, Received = 988, Lost = 12 (1% loss),
Approximate round trip times in milli-seconds:
Minimum = 22ms, Maximum = 43ms, Average = 24ms

[paul_dundee]

OpenSwan wasn't available in any 7 repository I could find so it was built from source on the 7 VM. I can't think of any other differences.

[TrevorH]

No idea what network card Hyper-V emulates. Can you post the output of lspci -nn | grep -i net so that we can tell.