TCP connections from host to guest drop on host network reconfiguration events.

[jglogan]

I have started seeing this behavior after upgrading to 4.3.4. It is 100% repeatable on my system, and has a pretty significant impact on productivity.

The forum article I posted is ​https://forums.virtualbox.org/viewtopic.php?f=8&t=58909.

Reproduction steps:

1.) Start guest VM
2.) ssh into guest (localhost:2322 forwarded to guest:22 in my config)
3.) Perform any of the following operations:
  a.) disable, then enable WiFi (issue occurs on enable, not disable)
  b.) disable VPN on host (happens with IPSecuritas and NetExtender VPNs on my system)
  c.) enable VPN on host

Expected behavior: no impact on ssh connection from host to guest

Actual behavior in 4.2.x: same as expected

Actual behavior in 4.3.4: ssh connection terminated, 'Connection to localhost closed by remote host.'

Config:

Host - MacOS 10.8.5, Guest - Ubuntu 13.04, 3.8.0-34-generic x86_64 Guest network - Paravirtualized network (NAT, natdnshostresolver enabled so that I can resolve VPN hostnames, but I have tested with it disabled and the same issue occurs) WiFi physical network connection

[jglogan]

VBox.log, network events at end of log file.

[vasily Levchenko]

Could you please collect pcap file of your ssh session?

[jglogan]

Guest-side capture, failure at 06:11:04.579

[jglogan]

Host-side capture, fails at 06:16:29.183.

[jglogan]

Guest-side capture.

[jglogan]

I used Wireshark on the host side and tcpdump on the guest side; please let me know if that's not okay.

host.pcapng and guest.2.pcap are captures of the same failure event from the host and guest side, respectively. guest.pcap is a capture of a separate failure, I just forgot to check the "replace attachement with same filename" when I uploaded guest.2.pcap.

Thanks! John

[jglogan]

Just curious, could this be a side effect of this bugfix for 4.3.4?

https://www.virtualbox.org/ticket/12225

[jglogan]

Another datapoint...I downgraded to 4.3.2 and I don't see the problem anymore. My guess is that the change for bug 12225 is causing this.