I have a server that I need VNC access to over the internet and I am having an issue. I referenced this site as the way to do it and went to establishing a direct connection over the internet. Here is what I did:
I have a block of 5 public ip addresses from my ISP and one of them I'm using to statically NAT from this internal server ( The RealVNC server is enabled on that internal server and I have connected to it over the LAN. I have confirmed that port 5900 is open on my public IP address with this website, but when I try to use VNC Viewer to connect to my public IP address, I get an error message saying "too many security failures."
I don't see which step I missed, what am I doing wrong that I can't access my VNC server?

  • Exactly how did you "statically NAT" your address? Nov 10 '17 at 22:01
  • @MichaelHampton ip nat inside source my.public.ip.address Nov 10 '17 at 22:08
  • Should the command be ip nat inside source static...?
    – joeqwerty
    Nov 10 '17 at 22:22
  • @joeqwerty yeah, sorry, editing right now Nov 10 '17 at 22:23
  • The "too many security failures" error implies you have made a connection successfully (so nothing is wrong with your NAT) but the VNC Server app has blacklisted the connection because of too many incorrect password attempts. Check the server logging to see if you are getting connection attempts from addresses other than the one you are expecting.
    – srk
    Nov 13 '17 at 10:34

Personally, when you need to manage a server behind a gateway that is connected to the Internet using NAT, I would suggest "easy to use" Real VNC or TeamViewer. Are freemium and if you don't need special requirements, those tools let you do the job done in few minutes. Hope it can help

  • That's what I'm using right now is RealVNC Nov 11 '17 at 5:12

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