Bhyve: virtio-net very slow with FreeBSD 12.0 Host

Dave Cottlehuber dch at
Sat Feb 9 07:21:18 UTC 2019

On Tue, 5 Feb 2019, at 22:16, Ole wrote:
> PS:
> i discovered the tool iperf. The connection from Host to VM is good,
> 6.36 Gbits/sec. The connection from Outside to host is also good, 847
> Mbits/sec.
> But from outside to the VM it is just 60.6 Kbits/sec. 
> Is there a generally problem with my setup?:
> em0 em0.4030(mtu 1400) tap0(mtu 1400)

I can’t speak for the specific config above, but generally this is a good time to reach for tcpdump(1) to capture some traffic on em0 and see if you can spot any anomalies especially in things like frame size (mtu related issues) and tcp checksums. See for a couple of things to check for there too. and the GUI app wireshark make a very nice combo.

Happy hunting.

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