ACLClouds
ACLClouds

Open a port without exposing the whole VPS

Allow the necessary protocol and source in the panel firewall and in Linux.

An application can be blocked by two layers: the ACLClouds/Proxmox firewall and UFW, nftables or iptables in the VM. Both must allow the same traffic.

Step-by-step procedure

  1. Check that the port is listening

    Before the firewall, check with ss -lntup that the application is listening on 0.0.0.0 or the desired interface.

  2. Choose protocol and source

    Only open TCP or UDP depending on the application. Limit the source address for SSH, database and administration.

  3. Add the panel rule

    In Tools VPS > Firewall, create the rule then check its direction and priority.

  4. Add the Linux rule

    Allow the same port in UFW or nftables, then test from an outside machine.