How to forward localhost + a port into a Windows VM

Question

I'm on a Mac running a Windows VM in Parallels, I'd like to - from my mac - be able to hit http://localhost:44300 and have that request served by an application running inside the VM.

I know that this is possible since when I run docker, that is in fact what it does, I can create an application, run it in the docker container on port 44300, then hit localhost:44300 from the host machine. I simply do not know how to configure my Windows + VM to do it.

So I created a simple webserver in nodejs that just replies with a timestamp. This works when hit from inside the virtual machine:

My netstat at this point reads

 TCP    127.0.0.1:44300        :0                     LISTENING

At this point, trying to curl from the host of course doesn't work

 $ curl http://localhost:44300
 curl: (7) Failed to connect to localhost port 44300: Connection refused

So to open this up to the host machine I forward the port in Parallels on my NAT configuration

I also create a urlacl rule:

PS C:\Users\gmauer> netsh http show urlacl | select-string 44300 -Context 1,5


>     Reserved URL            : http://*:44300/
          User: \Everyone
              Listen: Yes
              Delegate: No
              SDDL: D:(A;;GX;;;WD)

Now, when I curl I get something different

 $ curl http://localhost:44300 --max-time 3
 curl: (28) Operation timed out after 3004 milliseconds with 0 bytes received

This seems to be due to my Windows firewall. I (temporarily) disable it:

Set-NetFirewallProfile -Profile Domain,Public,Private -Enabled False

and now I get something different yet again

 $ curl http://localhost:44300 --max-time 3
 curl: (56) Recv failure: Connection reset by peer

Which seems to me that the request is passing into the VM but being shut down by something inside the VM (my understanding is that's the peer).

To confirm that I open up wireshark where I see the following:

So the VM sees the request, then something Resets it with an RST...And there I run out of ideas what else needs to be done.

I've had it suggested to me that the issue is that localhost is special (it of course is), but I think I've demonstrated above that the request is getting into the VM, its getting past the firewall, its just not going any further. What else can I check/do?

Edit 1: As a this-sounds-crazy-but-I'll-try-it, I tried to map localhosts to my guest IP in my windows hosts file - no dice, same result.

Edit 2: I've tried running netcat to set up a socket server and can telnet in from the host and send messages to the socket server. This beyond a doubt proves that requests are getting into the vm. An interesting clue is that while wireshark shows the request, fiddler does not.

Answer 1

127.0.0.1 or localhost is a special IP/hostname. It only works when you are referring to a port that is open on the current machine. You may have circumvented this by forwarding a port from the VM host to the VM guest, but probably the more robust solution is to use the IP address of the virtual machine. Connect directly to the guest; skip over all the firewall rules, forwarding rules, and address translations. You are making this too difficult.

Just run ipconfig from within your guest, get the IP, and use that instead.