VM's open ports not visible from outside of VM

MarekW

New Member
Apr 29, 2023
16
0
1
Krakow
Hi,
I just installed a Discourse forum engine on Ubuntu VM. The installation went great, but I am unable to open the Discourse site from my network over 443.

When I check open ports of the VM from external I see this:
1713508893199.png

But from inside (of the Ubuntu VM) I see this:
1713508980453.png

So, apparently no ports except SSH are visible from outside of the VM.
Any idea what I am doing wrong?

No firewall is enabled on PVE.

Thanks!
Marek
 
Hi,

No firewall is enabled on PVE.
At all? Since the 22 Port is open and the other, I would check if there is firewall enabled on (PVE, VM, or inside the Ubuntu VM itself).

May you tell us how you forwarded the 443? i.e., is that from the network configuration? Or the VM has a public IP?

Lastly, I would check tcpdump when you do nmap on ports 80/443
 
Hi,


At all? Since the 22 Port is open and the other, I would check if there is firewall enabled on (PVE, VM, or inside the Ubuntu VM itself).

May you tell us how you forwarded the 443? i.e., is that from the network configuration? Or the VM has a public IP?

Lastly, I would check tcpdump when you do nmap on ports 80/443
Yes, the firewall is disabled on the Datacenter level:
1713513358946.png

443/80 is being passed by Docker:
1713513454830.png

Now enabled the Ubuntu firewall (ufw) and allowed those ports. It changed as now I can see them while doing nmap, but they show as closed:

1713513597870.png

So, I am not sure now (not an expert on that matter) whether it is Docker or Ubuntu settings involved. Probably nothing on the PVE level.

Marek
 
This might be the reason then, but it's hard to know without seeing the settings of ufw.

Code:
sudo ufw status verbose

If it's a matter of the ports are open but only to localhost, for example, then changing the ufw settings will probably fix it.
 

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