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How to use the RustDesk remote control tool in IDEAL ADMINISTRATION?

Why does RustDesk work on the LAN but not over the Internet?

RustDesk works correctly when the computers are on the same local network, but the connection fails as soon as the remote computer is outside the company network or used for teleworking.

Why does this happen and what should be checked?

➡️ Why does RustDesk work on the LAN but not over the Internet?

RustDesk may work perfectly on the local network, but fail to establish a connection when the remote computer is outside the company network, for example when teleworking, on a remote site, or behind an Internet box.

This behavior is normal to diagnose because the two operating modes do not rely on the same network constraints.

On the LAN, the connection can often be established directly between the administrator computer and the remote computer. Over the Internet, RustDesk usually needs to use an ID server and, if necessary, a relay server.

➡️ Difference between a LAN connection and an Internet connection

On the local network, the administrator computer and the client computer can communicate directly using their internal IP address, provided that local firewalls and network rules allow it.

In this case, no external RustDesk server is necessarily required to establish the session.

However, for a connection over the Internet, the remote computer generally cannot be reached directly using its local IP address. RustDesk must then use:

• an ID server to identify and locate RustDesk computers
• a relay server when a direct connection is not possible
• a correct server configuration on both computers
• outgoing connections allowed to the RustDesk server being used

If one of these elements is blocked or incorrectly configured, RustDesk may work on the LAN but fail over the Internet.

➡️ The computer may be using LAN-only mode

The first check is to make sure that RustDesk is not configured only for local network use.

A LAN-only configuration may prevent RustDesk from using an ID server or relay server to establish connections over the Internet.

This mode may be intentional in environments where the company wants to block all connections to an external server, but it is not suitable for teleworking or off-site computers.

If you want to use RustDesk over the Internet, make sure that the RustDesk configuration applied from IDEAL ADMINISTRATION allows the use of the intended RustDesk server.

➡️ The configured RustDesk server may not be reachable

To work over the Internet, RustDesk must be able to reach the configured server.

Depending on your configuration, this may be:

• the secure Pointdev RustDesk server: rustdesk.pointdev.net
• a public RustDesk server
• a custom RustDesk server owned by your organization

If the remote computer cannot reach this server, the ID-based or relay connection cannot be established.

From the client computer, you can test access to the Pointdev RustDesk server with PowerShell:

• Test-NetConnection rustdesk.pointdev.net -Port 21116

You can also test the relay port if necessary:

• Test-NetConnection rustdesk.pointdev.net -Port 21117

If these tests fail, the blockage is probably caused by the firewall, proxy, DNS filtering, a network security solution, or an Internet access restriction.

➡️ RustDesk ports may be blocked

In some environments, outgoing connections are filtered. This may prevent RustDesk from contacting its ID server or relay server.

The most commonly used RustDesk ports include:

If your company uses a strict firewall, a filtering proxy, or DNS filtering, these flows must be allowed to the RustDesk server being used.

For the secure Pointdev RustDesk server, the domain to allow is:

• rustdesk.pointdev.net

➡️ A proxy or DNS filtering may block the connection

In some companies, Internet connections must go through a proxy, DNS filtering, an application firewall, or a security solution that blocks certain outgoing flows.

In this case, RustDesk may work on the LAN because no Internet access is required, but fail as soon as it needs to contact an external RustDesk server.

The points to check include:

• the RustDesk server DNS name is correctly resolved
• outgoing connections to the RustDesk server are not blocked
• the company proxy does not block the flows used by RustDesk
• the antivirus or EDR does not block the RustDesk process
• no security rule blocks the required RustDesk ports

➡️ The RustDesk server configuration may be incorrect

If you use the secure Pointdev RustDesk server or a custom RustDesk server, the configuration information must be correct.

Check in particular:

• the configured ID server
• the configured relay server
• the RustDesk key used, if your configuration requires one
• the connection mode selected in IDEAL ADMINISTRATION
• the correct application of this configuration on the client computer

An error in the ID server, relay server, or RustDesk key may prevent the Internet connection, even if the local connection continues to work.

➡️ Restart the RustDesk service after a configuration change

After changing the RustDesk configuration, it may be necessary to restart the RustDesk service so that the new settings are correctly applied.

If RustDesk continues to use an old configuration, it may still try to contact an old public server, an old custom server, or operate in a mode that is not suitable for Internet connections.

From IDEAL ADMINISTRATION, you can manage the RustDesk service remotely when the workstation administration prerequisites are available.

➡️ The remote computer may be behind a very restrictive network

Some public networks, hotels, mobile connections, company firewalls, or filtered Internet accesses may block the flows required by RustDesk.

In this case, the remote computer may work correctly when connected to the company LAN, but no longer be reachable when using another Internet connection.

It is then useful to test the connection from another network, for example another Internet connection or a mobile hotspot, to confirm whether the blockage comes from the network being used.

➡️ Priority checks

If RustDesk works on the LAN but not over the Internet, check the following points:

• RustDesk is not configured in LAN-only mode
• the ID server and relay server are correctly configured
• the client computer can reach the RustDesk server being used
• the required RustDesk ports are not blocked
• DNS correctly resolves the RustDesk server name
• the proxy, firewall, antivirus, or EDR does not block RustDesk
• the RustDesk service has been restarted after the configuration change
• the connection has been tested from another Internet access in case of doubt

In practice, when a RustDesk connection works on the LAN but not over the Internet, the issue is almost always caused by an unreachable RustDesk server, a configuration not suitable for Internet mode, a blocked port, or network filtering.

With IDEAL ADMINISTRATION, it is recommended to check the RustDesk configuration applied to the computer, test access to the server being used, and then restart the RustDesk service if changes have been made.