I've been connecting to my Mac with the iOS VNC app to monitor a process remotely, and noticed Firewall was turned off in Security & Privacy. enter image description here

So of course I turned it back on, and tried to connect again with VNC. The connection fails with "The computer's network could not be contacted." With "Stealth Mode" disabled, VNC still will not connect.

The obvious solution here would be to approve VNC logins:

The same way SSH is enabled, but clicking the "+" brings up a drop-down menu to select an application.

Checked VNC's support site, but they have outdated information: https://support.realvnc.com/knowledgebase/article/View/269/12/how-do-i-allow-connections-through-my-firewall

What am I missing here?

  • Are you using OS X's built-in VNC server? Jun 17 '15 at 21:36
  • Believe so, it's RealVNC connecting by IP.
    – Rampant
    Jun 17 '15 at 21:38
  • Using either a different Mac or the server itself try typing in the following into the terminal: nc -v 5900 Replace with whatever your server's IP is and post the results. Jun 17 '15 at 21:40
  • with nmap I get: Completed Ping Scan at 15:02, 3.00s elapsed (1 total hosts) Nmap scan report for 192.168.x.xxx [host down] Read data files from: /usr/local/bin/../share/nmap Note: Host seems down. If it is really up, but blocking our ping probes, try -Pn Nmap done: 1 IP address (0 hosts up) scanned in 3.38 seconds and it will be obvious why when I post the solution...
    – Rampant
    Jun 17 '15 at 22:20

Enabling the firewall changed the SSH/VNC connection IP. I changed it to the correct IP in the iOS VNC app, and can now connect even with Stealth Mode enabled on the client Mac.

The Sharing Control Panel clued me in, as the IP shown wasn't the one entered in the VNC app: enter image description here


This has helped me in fixing the issue on Hi Sierra.



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