TransPort routers can be configured in order to use SSH for TCP Socket connection to the serial port, this is useful if you would like to access via SSH to a device connected to the serial port of the TransPort.
In order to configure this, the basic idea is to configure an SSH server listening to a specific port, to forward the connection to the local port on which the ASY port is listening to:
1) Navigate to the WEB UI section Configuration-Netwrok > SSH Server > SSH server 1 and configure the settings as the picture below:
Regarding the settings above please note:
- SSH server 1 is used for this purpose, instead of SSH server 0 that is by default the one to use for access the TransPort itself.
- Use TCOP port: 2001 is just an example and can be changed to another number
- Hostkey 1 Filename: All new Digi Transport routers have a factory generated private key named privSSH.pem and this is the one used in this example. If you need to generate a new one, please refer to the section 2.1 of teh document at: http://ftp1.digi.com/support/documentation/transport/assets/guides/QN_019_Using_SSH_tunnelling_to_securely_manage_a_router_with_HTTP.pdf
- You have to spread SSH sessions over the SSH Servers, so for each SSH Server be sure to set “Allow up to X connections” to 1.
- The Port forwarding is configured with "127.0.0.1" address and "4000" port, as the connection must be forwarded to the TransPort itself on the local port (4000 in this example) on shich the ASY port, connected with the serial device behind the TransPort, is listening to.
- If you need to configure the same for other serial ports, use the other SSH Servers (SSH Server 2, etc.) and follow the same logic, i.e. 2002 -> 4001.
2) Test the configuration: connect the Transport to the Local COM port of a computer or another serial device and open a SSH connection with an application like PuTTy to the IP address of the Transport and TCP Port 2001:
Data is sent from TCP socket and received on COM1:
You can see the connections estabilished going to: Management – Connections > IP Connections > General Purpose Sockets:
Please note that for general configuration of the serial port using TCP socket (not SSH), the TransPort routers have a built int Wizard that guide you in the setup and instructions can be found here: http://ftp1.digi.com/support/documentation/QN_037_Configuring_a_transport_serial_port_for_tcp_socket.pdf.