Hello, I have a LAN with an IP scheme of 192.168.127.xxx and a small PLC network with a scheme of 10.56.1.xxx (Compactlogix & PointIO). I am looking to use a Moxa NAT-102 device to facilitate communication between the two networks. This setup is crucial for my SCADA system, which needs to be on the LAN but access tags on the PLC network. I have configured the NAT ports to align with their respective networks (internal=PLC network=10.56.1.200, external=LAN=192.168.127.250) and can successfully communicate with the NAT. However, I am facing challenges getting RSLinx to communicate through the NAT and access the PLC IPs on the network. Even pinging the PLCs through the NAT is proving to be difficult. The Moxa dashboard indicates that the NAT ports are assigned and active, responding appropriately when the PLC network is disconnected from the NAT. I am seeking advice on how to effectively communicate and ping the PLCs through the NAT. Your help is greatly appreciated!
Are the routing table and gateway address properly configured in the NAT device for seamless communication with external networks? Ensure the PLC and other relevant devices are set to the NAT device's address to facilitate connectivity with outside networks.
I have configured the routing table properly, but have yet to input the gateway address on the PLC. I will double-check this to ensure accuracy. Thank you!
Why should the SCADA system be on a different LAN than the PLC in a corporate network? One effective method is to set up dual hosting for the SCADA Server with two NIC cards, one for the PLC LAN and one for the Corporate LAN. By configuring the server's firewall to only open ports for SCADA clients, security can be enhanced. For additional protection, consider placing a firewall between the Corporate network and the SCADA Server instead of relying solely on the server's software firewall. It is advisable to keep SCADA clients isolated from the IT network to minimize potential risks, as operational technology (OT) and information technology (IT) should remain separate to avoid complications.
NAT devices serve as simplified routers with various features, including the common "1 to 1 NAT" function that disguises internal IP addresses as external ones. The terms "public" and "private" refer to different IP subnets, such as the internal PLC LAN and external enterprise LAN. For example, while an internal network may use a common corporate address range like 10.x.y.z, the external network may utilize a smaller range like 192.168.y.z. The Moxa NAT-102 user manual explains 1-to-1 NAT in detail. Typically, when using Class C networks, the host numbers on the external and internal sides may remain the same. This is just one way NAT devices are used, as they can also function as regular routers or be part of a VLAN. Setting the "default gateway" on a PLC or embedded device is crucial for remote access. Configuring devices like CompactLogix and POINT Adapter to the administrative IP address specified by the NAT device can enable remote connectivity. Additionally, using tools like Test-NetConnection (tnc) in Windows PowerShell can help verify TCP/IP connectivity to devices like ControlLogix. Troubleshooting routers and control devices often involves using tools like TNC, web browsers, and others to ensure basic connectivity before attempting to use RSLinx. It's important to test and report your findings for further assistance.
Thank you to everyone who provided answers. Your assistance is greatly appreciated. As a beginner in networking, I am still navigating the learning curve. My current setup consists of a single PLC, a NAT, and my PC. To outline my system configuration: The PLC's IP address is 10.56.1.200, as shown in the controller properties. The NAT has been configured with an internal port of 10.56.1.201 and an external port of 192.168.127.254, matching my PC's network settings. The NAT settings are set to 1-1, with the translated port of 10.56.1.200 and a destination port of 192.168.127.200. Despite reaching out to Moxa tech support with no success, I have been unable to access the translated IP 192.168.127.200. I can configure the NAT using a browser window, but Linx remains inaccessible. Your support has been invaluable, and I will be sure to revisit and implement the advice provided later today. This website has proven to be an excellent resource for troubleshooting. Thank you again for your help.
It sounds like you're on the right track with your Moxa NAT-102 setup! One thing to check is if your RSLinx configuration is set up to use the right driver for the PLCs, as that can often be a sticking point. Make sure you also have the Moxa configured to allow the necessary traffic types through its firewall features. Additionally, verify that the NAT translations are correctly configured and that routing is properly set up between both networks. Sometimes, adding static routes on your devices might help them find each other more easily. Have you tried looking at the logs on the Moxa device? They can provide insights into any blocked attempts or configuration-related issues.
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Answer: Answer: Troubleshooting steps can include verifying the NAT port configurations, ensuring proper network settings on both sides, checking for firewall issues, and confirming that the devices are able to communicate with each other through the NAT.
Answer: Answer: Common challenges can include incorrect port configurations, network conflicts, firewall restrictions, and issues with routing or NAT translation settings.
Answer: Answer: You may need to ensure that RSLinx is configured to communicate through the NAT device's IP address and port, as well as check for any additional settings required for cross-network communication.
Answer: Answer: Challenges with pinging PLCs through a Moxa NAT device can arise from misconfigured network settings, firewall restrictions blocking ICMP traffic, or issues with routing and NAT translation settings on the device.
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