About IronVNC Clients

Hello

Our VNC integrations (FreeVNC / IronVNC) are built-into RDM and not a separate download or installation. When you configure a VNC session inside RDM, using the "Embedded" mode (which is the default) you'll have the choice of both these clients; and the session is run within RDM. If something's not clear or you need further guidance, please don't hesitate to post back as I'd be happy to upload some screenshots or further information.

We don't provide a standalone VNC client outside of our core products (RDM, Devolutions Gateway and Devolutions Server).

I don't recommend using IronVNC inside RDM at this point. The integration is still experimental and it's missing a lot of features and options that FreeVNC has. So far our focus on IronVNC has been for the web, but we are working to uplift the desktop integration and make it a first class option in the medium term. For now - I recommend choosing FreeVNC.

If you have any problems configuring or connecting to a VNC server from within RDM, please don't hesitate to let me know.

Kind regards,

Hello

Our VNC integrations (FreeVNC / IronVNC) are built-into RDM and not a separate download or installation. When you configure a VNC session inside RDM, using the "Embedded" mode (which is the default) you'll have the choice of both these clients; and the session is run within RDM. If something's not clear or you need further guidance, please don't hesitate to post back as I'd be happy to upload some screenshots or further information.

We don't provide a standalone VNC client outside of our core products (RDM, Devolutions Gateway and Devolutions Server).

I don't recommend using IronVNC inside RDM at this point. The integration is still experimental and it's missing a lot of features and options that FreeVNC has. So far our focus on IronVNC has been for the web, but we are working to uplift the desktop integration and make it a first class option in the medium term. For now - I recommend choosing FreeVNC.

If you have any problems configuring or connecting to a VNC server from within RDM, please don't hesitate to let me know.

Kind regards,

@Richard Markiewicz


So that said, FreeVNC still cannot do file transfers, right? I had originally switched from TightVNC to RealVNC due to the etter UI and interface but no file transfers caused me to then switch to RustDesk.

I eventually came to RDM for VNC since it could open multiple sessions at a time (unlike RealVNC Lite) but the lack of File Transfers is a sore point and I don't want to use an external option because then I'd just be back to TightVNC all over again...


Edit: I should also add that I also tried the MightyViewer trial (great but don't want to pay that much) and Remote Ripple which is also really great, except you can't pop out different tabs into new windows.

Hello

FreeVNC can do file transfers with UltraVNC servers.

The problem from our side is the fragmentation that exists in VNC, there is no specification for "file transfer" and it's implemented as a vendor-specific extension to the protocol. In general it works with a specific client and server implementation, and different clients do not support other vendors servers.

RealVNC is closed source and closed specification, the only way to implement their file transfer protocol is by reverse engineering which is extremely costly.

UltraVNC and TightVNC are open source. We reimplemented the UltraVNC file transfer in freevnc based on customer demand and to close a specific feature gap. We haven't reimplemented TightVNC file transfer in freevnc as the customer demand simply hasn't been there. IronVNC has it; as a greenfield project it was easier to add; but the integration with RDM is not there yet.

It's unlikely that TightVNC file transfer will ever be done in freevnc at this point. We plan an engineering effort to replace freevnc with ironvnc in RDM, and I would like to see that happen over the next major versions (potentially by 2026.2 or .3, so the middle to second half of next year). But unfortunately right now, if you need VNC and file transfer the only suggestions I have are to use an UltraVNC server or an external VNC client.

I apologize for the inconvenience

Kind regards,

Hello.
I am using Vino-server on Ubuntu. FreeVNC cannot connect to the server.
Server reports: Security types supported TLS (18) and VNC (2). Client selects Security type TLS (18), then Unknown (22) and disconnects.
IronVNC immediately selects VNC (2) and connects successfully.
How can I force FreeVNC to use VNC (2)?

Hello

Ok, interesting - this sounds very similar to another report I had recently.

Currently there's no way in RDM to force a specific security method. FreeVNC allows it, but we don't expose that control in RDM.

I'm mainly interested in why TLS Authentication is failing, and why IronVNC is selecting VNC authentication. TLS is more secure so if the server offers it, it should be chosen by default.

I wonder if Vino is presenting a certificate with an unsupported crypto algorithm. Neither FreeVNC or IronVNC support insecure crypto (TLS earlier than 1.2).

Since I understand what server you're using, I will try to reproduce this on my side and make a fix (and I'll look at allowing specific auth package selection at the same time).

Thanks for your patience and sorry for the inconvenience

Kind regards,

Hello again

Ok, I've dug into this now. FreeVNC will prefer TLS as the more secure authentication method (if encryption is available, why not use it?). TLS authentication is a security type specific to Vino; after negotiating the authentication we proceed to upgrade the transport to TLS. That's what's happening - I suppose you used Wireshark or another packet dissector, but the "Unknown (22)" response is Wireshark misinterpreting the TLS ClientHello as a VNC message, and getting the content wrong. After we send the ClientHello, the server immediately closes the connection and I'm not 100% sure why but I suspect a TLS version mismatch or incompatible cipher suites. On the FreeVNC side we only support TLS 1.2 and upwards. Vino appears to be archived and unmaintained since at least 2020 so I suspect it's using an older TLS version. I have no way to validate that because I cannot find any VNC client that can connect to this configuration (and inspect a working TLS handshake).

IronRDP selects the authentication type by weighting them according to preference, but TLS authentication doesn't have any weight so VNC is chosen instead.

I'll fix the issue by applying the same logic to FreeVNC and that will be available in an upcoming minor update. I'll post back once this is available. I'm not opposed to adding a setting to allow the user to select the security type, but this change should solve your immediate issue.

Please, let me know if you have any questions or comments

Kind regards,

Hello again

I'm confident this issue will be resolved in the upcoming 2025.3.30 release, which should be available within the next couple of weeks. Thanks for your patience.

Kind regards,

Hello.
Thank you for your reply.
I tried using the TigerVNC server, and the connection works fine with it. I will probably replace Vino with TigerVNC.