Tunnel – 4G-Serial Tunnel with SSL security. MTX-Tunnel configured as TCP/IP Client connected to GPRS permanently using a SIM card with a dynamic IP address

Scenario details:

• There are three devices with RS232 (configured as 9600,8,N,1 and without flow control) which send information on a regular basis through the serial port. We want to collect and store all of that information from a PC server located at the central office
• The PC server waits for incoming connections from the different MTX-Tunnels. This means that the server PC does not connect with the MTX Tunnel; instead it is the MTX Tunnel which connects to the office IP address where the PC server is located (this is “oficina.midominio. com” and TCP 20010 port)
• The PC software control supports SSL socket communications and, as the information sent is very sensitive, it is important that we block access to this it, even if Ethernet sniffer is used (within the own LAN net where the PC server is located)
• MTX-Tunnel modems must remain permanently connected to the PC server, as information is frequently sent. MTX-Tunnel connects to the central office IP address so it does not make sense to use a SIM with fixed IP. Instead, SIMs with dynamic IP addresses will be used which are much cheaper

Solution: MTX-Tunnel firmware + MTX-Java-IoT/MTX-Java-T/MTX-Java-T2

Config.txt configuration file:

Configuration

Observations

COMM_baudrate: 9600 COMM_bitsperchar: 8 COMM_autocts: off COMM_autorts: off COMM_stopbits: 1 COMM_parity: none GPRS_apn: movistar.es GPRS_login: MOVISTAR GPRS_password: MOVISTAR GPRS_DNS: 8.8.8.8 GPRS_timeout: 0 MTX_PIN: 0000 MTX_model: MTX-4G-JAVA-IOT-STD-N MTX_mode: client MTX_IDClient: equipoX MTX_urc: off MTX_clientSSL: on TCP_IP: oficina.midominio.com TCP_port: 20010

Serial port baud rate 8 bit data CTS hardware control disabled RTS hardware control disabled 1 stop bit No parity GPRS APN from your network operator GPRS Login GPRS Password DNS server IP address Modem is connected to GPRS permanently If SIM card has no PIN security, use 0000 value MTXTerminal modem model used TCP client mode MTXTunnel identification string different for each modem URC messages will not be sent SSL secure communication enabled Server IP address or DNS information Server TCP port for connection

Details:

• Remember MTX-Tunnel can only make SSL connections if it is configured in “client” mode
• You can install SSL Root certificates according to your needs. Check Annex C for more information