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Question Can't connect Windows VNC Viewer to Tigervnc on Ubuntu guest on vSphere


Junior Member
May 3, 2019
I'm trying to VNC from my Windows PC to my Ubuntu 18.04.1 guest running on vSphere 6.7.0 on the same network (subnet and just can't. I'm guessing this is an ESXi issue, but it could be Windows or possibly Ubuntu.

Client side:
-Windows 10 (wifi)
-VNC Viewer 6.19.325

Server side:
-Ubuntu 18.04.1 guest on vSphere 6.7.0 hypervisor
-tigervnc 1.7.0 on port 5901

Here's what I've done:

-Disabled the Ubuntu firewall (as a troubleshooting step)
-Disabled Windows Defender (ditto; curiously this changed the error from a timeout to refused-by-host)
--I also tried explicitly allowing outgoing connections to remote ports 5900-5999, but that didn't seem to do anything
-Allowed ports 5900 through 5999 through the vSphere firewall for incoming TCP connections.
-Configured the following settings in my vmx file and re-registered and re-booted the Ubuntu VM:
--RemoteDisplay.vnc.enabled = "TRUE"
--RemoteDisplay.vnc.port = "5901"
-Sniffed traffic on both Windows and Ubuntu. Same thing on both. I see a Win->Ub TCP SYN followed by some Ub->Win RST, ACK packets alternated with Win->Ub TCP retransmissions. Nothing after the third RST, ACK.

It's worth noting that these work:

-VNCing from the Ubuntu guest to itself over port 5901.
-SSHing to the Ubuntu VM from the Windows box using the Secure Shell Chrome app on port 22.

[edit] I gave up. I'm using TeamViewer now. By the way, if you use TeamViewer on Ubuntu, a word to the wise: the account password has a different maximum length than on Windows, but the application does nothing to indicate this. If you copy/paste your password, you'll just get a "username and passwords do not match any accounts on record" error. I don't know if the password field truncates the password (hard to tell with asterisk masking) or if it's a more internal issue. 50 characters is apparently too long. 25 is short enough.
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