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J-Link Remote Server

J-Link Remote Server (previously called J-Link TCP/IP Server) is a small server application that allows using J-Link / J-Trace remotely via any TCP/IP hardwired (Ethernet) or wireless (WiFi) network.

Pros using J-Link Remote Server

  • Using J-Link even in large development environments where the target hardware is not at the same location as the PC running the debugger.
  • SEGGER remote support for device vendors when implementing support for new devices for which silicon is not available yet. So, usually there is no longer the need for chip vendors to send hardware when support for a new device, which is still in prototype stage, is needed.


J-Link Remote Server is distributed as part of the J-Link software and documentation package and can be used free of charge.  

Remote Server Usage

The configuration of the J-Link Remote Server is kept as simple as possible. It works out-of-the-box without special configuration. All that is needed at the time when starting the Remote Server is a J-Link that is connected to the PC. In general, connection to J-Link via Remote Server is supported by all Applications/IDEs which support connection to debugger via Remote. The following screenshots show to how to configure J-Link Commander, J-Flash and IAR EWARM in order to connect to an J-Link via Remote Server.
In those examples, the PC the J-Link Remote Server is running on has the ip address

The screenshot shows how to connect to a J-Link via the J-Link Remote Server.

The screenshot shows how to configure J-Flash in order to connect to a J-Link via the J-Link Remote Server.

The screenshot shows how to configure IAR EWARM in order to connect to a J-Link via the J-Link Remote Server.

The screenshot shows the Remote Server a client has already connected to.

Remote Server in Tunneling Mode

Remote connection to a J-Link or J-Trace

The Remote Server provides a tunneling mode which allows remote connection to a J-Link / J-Trace from any computer, even from outside the local network. Making the entire J-Link family of debug probes, support use over a WAN .

To give access to a J-Link neither a remote desktop or vpn connection nor changing some difficult firewall settings are necessary.

When started in tunneling mode the Remote Server connects to the SEGGER tunnel server via port 19020 and registers with its serial number. To connect to the J-Link from the remote computer an also simple connection to tunnel:<serialno> can be established and the debugger is connected to the J-Link.</serialno>


Example Usage Scenarios

1. SEGGER access to hardware

A device vendor is developing a new device which shall be supported by J-Link. Because there is only one prototype, a shipment to SEGGER is not possible. The tunneling mode of the Remote Server allows the vendor to give SEGGER access to the prototype hardware without the need of sending it to SEGGER. All that is necessary is to connect a J-Link to the hardware, start the Remote Server in tunneling mode and provide SEGGER the serial number of the J-Link, so SEGGER is able to remotely connect to the J-Link and debug on the hardware. 

2. Engineer access to hardware

For example a large European corporation which sells software that can be used with J-Link (IDEs, custom applications, ...), has an Indian customer whose software is behaving strangely when using it with their target, but the number of available hardware samples is very limited or the setup is quite big and cannot be simply moved so the hardware cannot be sent. The tunneling mode allows the engineers from Europe to remotely connect to the J-Link in India without having the hardware on their desk. Moreover, the engineers from Europe can start their application out of the debugger without the need to install their sources on the customer PC as it would be the case for a VNC connection etc. This setup clearly shows advantages for both, the accessing side (the engineer in Europe) and the target side (the Indian office), especially over VNC or desktop-sharing connections:

  • On the target side no time is needed for setting up a compile/debug system. Only J-Link Remote Server needs to be started, which is very easy to do.
  • Only the accessing side needs the debugger software, as well as the license for this.
  • The target side does not need to have all sources for debugging a problem.

Remote Server Usage in Tunneling Mode

Start J-Link Remote Server in Tunneling Mode

To start the Remote Server, select J-Link Remote Server (Tunneling mode) from the main menu.

The connection was successful
Remote Server, a client has already connected to

Verify the connection via J-Link Commander

J-Link Commander can be used to verify a connection so the J-Link can be established as follows: 

  • Start J-Link Commander 
  • From within J-Link Commander enter: ip tunnel:<SerialNo>

The network transfer of a successful connection

Test connection status

To test whether a connection to the tunnel server can be established or not a network protocol analyzer like Wireshark can help.


Problem Solution
Remote server cannot connect to tunnel server 1. Make sure the Remote Server is not blocked by any firewall.
2. Make sure port 19020 is not blocked by any firewall.
3. Contact network admin.
J-Link Commander cannot connect to
tunnel server

1. Make sure Remote Server is started correctly.
2. Make sure the entered serial number is correct.
3. Make sure port 19020 is not blocked by any firewall.
4. Contact network admin.