virtualbox.org

ChrisLi wrote:I just set up a new CentOS7 VM with btrfs..
.. configured the port forwarding as ever..
.. and it works again..
No reason detected; just a bug.

That probably means that it is an issue with the configuration of the one guest that doesn't work correctly rather than it being a bug in VirtualBox.

ChrisLi wrote:Bad Support here

This is a user to user forum where folks who have been using VirtualBox for a long period use their free time to help others. If you want support and a service level agreement then you need to get your cheque book out and track down your local Oracle sales folk.

ChrisLi wrote:or he had no time to look into it

Whilst their are a number of folks around here who use macOS as a host OS our "in-house expert" has been away from the forums for a short while so probably hasn't seen the messages.

-Andy.

In 2021, I put what I found on centos 8.
Actually there are 2 default NICs will be installed on VM, enp0s3 and virbr0, (ubuntu will only have one enp0s3).

If you set port forwarding on virbr0, then you can still see "Connection established." in verbose of ssh, even enp0s3 is not activated. And you will see " kex_exchange_identification: read: Connection reset by peer"

You need activate enp0s3, which open the door to outside world.