Solved! Hooray!
This problem has been solved by the author...
In general, port forwarding works for me.
Currently I want to add a port, 80 to 8080, host to client, but i just cannot use port 80 on my host.
e.g.
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/GuestPort, Value: 22
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/HostPort, Value: 2222
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/Protocol, Value: TCP
works, i can login on www.mydomain.tld:2222 via ssh. bam!
Trying 80 to 8080
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/nginx/GuestPort, Value: 8080
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/nginx/HostPort, Value: 80
Key: VBoxInternal/Devices/pcnet/0/LUN#0/Config/nginx/Protocol, Value: TCP
does not work, netstat also does not show me any listening on port 80 on host-linux.
I dont know how to debug that, tailing the log gives me:
00:00:00.373 Changing the VM state from 'CREATING' to 'CREATED'.
00:00:00.374 Changing the VM state from 'CREATED' to 'POWERING_ON'.
00:00:00.374 NAT: set redirect TCP host port 2222 => guest port 22 @ 10.0.2.15
00:00:00.374 NAT: set redirect TCP host port 80 => guest port 8080 @ 10.0.2.15
00:00:00.374 NAT: failed to redirect TCP 80 => 8080
00:00:00.375 Changing the VM state from 'POWERING_ON' to 'RUNNING'.