It seems to depend on whether you enter 127.0.0.1:8888 or localhost:8888 in your browser:
- 127.0.0.1:8888 shows port 2222
- localhost:8888 shows port 22
Screenshot attached.
I think I figured it out. I was able to verify the two different ports (2222 and 22) are displayed based on it you hit 127.0.0.1:8888 or localhost:8888 in your browser as @Michael Häusler's side-by-side screenshot shows. I double-checked the port forwarding in VirtualBox as shown below.
No matter which way you hit it via the browser, we are always going to port 8888 on the Sandbox itself. It seems there is some logic in the webapp that you hit that leverages which address you used to get to it. Thankfully, the on-screen instructions drive you to use http://127.0.0.1:8888/.
If you look close, you'll see that the all the hostnames on that splash screen change between 127.0.0.1 and localhost based on the original URL you use. I believe the reason the webapp is doing this is based on if you were actually running a windowing system on the Sandbox itself. We are basically just SSH'ing in and aren't using a windowing interface.
My hunch then was that depending on where you are accessing this makes a difference and I did validate that by some SSH testing. If you are coming in from your host OS then you can only SSH over port 2222, but it doesn't matter if you say localhost or 127.0.0.1.
HW10653-2:~ lmartin$ ssh root@127.0.0.1 -p 22 ssh: connect to host 127.0.0.1 port 22: Connection refused HW10653-2:~ lmartin$ ssh root@localhost -p 22 ssh: connect to host localhost port 22: Connection refused HW10653-2:~ lmartin$ ssh root@localhost -p 2222 root@localhost's password: Last login: Wed Mar 2 23:18:00 2016 from 10.0.2.2 [root@sandbox ~]# exit logout Connection to localhost closed. HW10653-2:~ lmartin$ ssh root@127.0.0.1 -p 2222 root@127.0.0.1's password: Last login: Wed Mar 2 23:19:13 2016 from 10.0.2.2 [root@sandbox ~]#
Conversely, once you "in" the Sandbox (in the following case it doesn't matter if you SSH'd in or if you were logged in via a windowing manager) you can only use port 22; again, it doesn't matter how you refer to the hostname.
[root@sandbox ~]# ssh root@127.0.0.1 -p 22 Last login: Wed Mar 2 23:26:13 2016 from 10.0.2.2 [root@sandbox ~]# ssh root@localhost -p 22 Last login: Wed Mar 2 23:27:10 2016 from 127.0.0.1 [root@sandbox ~]# ssh root@localhost -p 2222 ssh: connect to host localhost port 2222: Connection refused [root@sandbox ~]# ssh root@127.0.0.1 -p 2222 ssh: connect to host 127.0.0.1 port 2222: Connection refused [root@sandbox ~]#
I'd have to put my networking cap on tighter than it is right now to fully explain why this is the case, but with these limitations in play of port 22 and 222 depending on if you are currently logged into the Host OS or the Guest OS, we really do need the splash screen to be dynamic like it is now.
That said, it is easy to see why one would get confused if they got creative and just started with http://localhost:8888 instead of http://127.0.0.1:8888 as the instructions said.
