# Ignition PLC on different subnet than server **URL:** \ **Category:** Ignition\ **Created:** [October 17, 2024, 2:48pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392 "2024-10-17T14:48:09Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![Grant\_Bargeloh](https://avatars.discourse-cdn.com/v4/letter/g/ecd19e/32.png) [@Grant\_Bargeloh](https://forum.inductiveautomation.com/u/Grant_Bargeloh)\ **Post date:** [October 17, 2024, 2:48pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/1 "2024-10-17T14:48:09Z")
Hello, I am hoping this is an easy questions that I just don't have much experience with networking but have a ControlLogix PLC who's IP is 192.168.1.1 with two ethernet cards as well in the rack. Our Ignition server in for testing is in our shop is on 172.20.10.165 network. I cannot figure out how to add the plc to the server. I thought I just had to setup the IP of one of the ethernet card on the 172 network but that did not work. ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [October 17, 2024, 2:53pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/2 "2024-10-17T14:53:20Z")
1. Show us your PLC's IP configuration. 2. Is the LAN port you are plugged into on the 172.20.0.0 network? 3. Is there a router involved? ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [October 17, 2024, 3:06pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/3 "2024-10-17T15:06:08Z")
> [@Transistor](#): > > Is there a router involved? This is key. EtherNet/IP class 3 messaging is fully IP routable (and NATable), so you don't **have** to be on the same subnet, as long as a router knows the path. ---
**Author:** ![Grant\_Bargeloh](https://avatars.discourse-cdn.com/v4/letter/g/ecd19e/32.png) [@Grant\_Bargeloh](https://forum.inductiveautomation.com/u/Grant_Bargeloh)\ **Post date:** [October 17, 2024, 3:23pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/4 "2024-10-17T15:23:54Z")
1. 192.168.1.1 subnet 255.255.255.0 2. yes 3. yes, I have it setup right now where the router is connected to the 172 network and I am able to connect to the ignition server and see the PLC in RSLinx at the same time ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [October 17, 2024, 3:29pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/5 "2024-10-17T15:29:12Z")
Post a photo of a sketch of the layout. Showing the IP addresses and subnet masks of each device (gateway, laptop, etc.) and both IP addresses for the router and where it sits in the network. ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [October 17, 2024, 3:34pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/6 "2024-10-17T15:34:24Z")
The PLC address needs to be in the same subnet as the LAN it is plugged into. (Per-card or port, if multiple cards/ports on the PLC.) ---
**Author:** ![Grant\_Bargeloh](https://avatars.discourse-cdn.com/v4/letter/g/ecd19e/32.png) [@Grant\_Bargeloh](https://forum.inductiveautomation.com/u/Grant_Bargeloh)\ **Post date:** [October 17, 2024, 4:11pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/7 "2024-10-17T16:11:48Z")
![Ignition Testing Network Drawing](https://us1.discourse-cdn.com/inductiveautomation/original/3X/f/0/f0ba93ddf032a9e7cde78b10a9a3cdb13f5b0d4a.jpeg) ---
**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\ **Post date:** [October 17, 2024, 4:33pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/8 "2024-10-17T16:33:17Z")
The dotted line path will definitely not work. If that router is a typical WAN/LAN combination, it will not route inward from its WAN port without a pinhole, and then the Ignition gateway would need to target the router's WAN port. ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [October 17, 2024, 4:45pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/9 "2024-10-17T16:45:08Z")
Your laptop and Logix is working because they are connecting to the 192.168.0.0 subnet which has the PLC 192.168.1.10 Ethernet card. For the gateway to connect you would have two standard options: 1. If the router supports multi-NAT then you would configure a WAN address like 172.20.10.120 and have that translate to 192.168.1.10 on the LAN side. IMPORTANT: you would need to configure the PLC's IP gateway setting (nothing to do with Ignition "gateway") to 192.168.1.225, the LAN address of the router. (Check that IP address. Your sketch is very difficult to read.) 2. Set up port forwarding on the router on port 44818 to 192.168.1.10:44818 and point the Ignition connection to the router, 172.20.10.119. ---
**Author:** ![Grant\_Bargeloh](https://avatars.discourse-cdn.com/v4/letter/g/ecd19e/32.png) [@Grant\_Bargeloh](https://forum.inductiveautomation.com/u/Grant_Bargeloh)\ **Post date:** [October 17, 2024, 5:38pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/10 "2024-10-17T17:38:43Z")
I attempted to do the port forwarding with no luck. I am pointing to the router. 172.20.10.119 ![OPC Client Setup](https://us1.discourse-cdn.com/inductiveautomation/original/3X/7/2/72ade0dd13d7d1346244e745169746a0e445ceff.jpeg) Forwarding 44818 to 192.168.1.10 ![Port Forwarding](https://us1.discourse-cdn.com/inductiveautomation/original/3X/c/c/cc776094da9204696cde3b000d0dea86aa6b2605.jpeg) The Ignition Gateway is still not seeing it. ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [October 17, 2024, 6:11pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/11 "2024-10-17T18:11:10Z")
The [Connecting to ControlLogix | Ignition User Manual](https://www.docs.inductiveautomation.com/docs/8.1/ignition-modules/opc-ua/opc-ua-drivers/allen-bradley-ethernet/connecting-to-controllogix) connection defaults to CPU in slot 0 (as shown in your screengrab). Confirm that your gateway configuration matches what RSLogix shows. Your port forwarding looks OK to me. ---
**Author:** ![Grant\_Bargeloh](https://avatars.discourse-cdn.com/v4/letter/g/ecd19e/32.png) [@Grant\_Bargeloh](https://forum.inductiveautomation.com/u/Grant_Bargeloh)\ **Post date:** [October 17, 2024, 6:42pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/12 "2024-10-17T18:42:08Z")
Controller is in slot 0. I wouldn't need to specify a connection path and to point to the backplane and then then to slot 0 would I? ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [October 17, 2024, 7:03pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/13 "2024-10-17T19:03:07Z")
Any I set up just worked so I can't help to much there. Someone else should be able to help. What you could do to rule out the router as a problem is: 1. With your laptop connected to the LAN via WiFi (as it is in your diagram) browse to 192.168.1.10. You should get the Rockwell page on the Ethernet module. If that works, ... 2. Temporarily change your router configuration to pass through port 80 to port 192.168.1.10:80. Now try browsing to 172.20.10.119 from the 172.20.0.0 network and see if the Rockwell page comes up again. If it does the port forwarding is working so it should work for Ignition when switched back to 44818. Have you configured the gateway in the Ethernet module? ```python IP: 192.168.10.1 Subnet: 255.255.255.0 Gateway: 192.168.10.225 (router's LAN address) ``` ---
**Author:** ![Grant\_Bargeloh](https://avatars.discourse-cdn.com/v4/letter/g/ecd19e/32.png) [@Grant\_Bargeloh](https://forum.inductiveautomation.com/u/Grant_Bargeloh)\ **Post date:** [October 17, 2024, 7:28pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/14 "2024-10-17T19:28:04Z")
It was the Gateway on ethernet module! Thank you so much for your help! ---
**Author:** ![Transistor](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/transistor/32/3380_2.png) [@Transistor](https://forum.inductiveautomation.com/u/Transistor)\ **Post date:** [October 17, 2024, 7:32pm UTC](https://forum.inductiveautomation.com/t/ignition-plc-on-different-subnet-than-server/97392/15 "2024-10-17T19:32:15Z")
It took me most of a day to learn that many years ago. When you don't configure the gateway the module receives the Ethernet request but, since the sending IP address fails the subnet mask compare, the module hasn't a clue how to send the response out onto the wider network. The gateway configuration does this. **Commit to memory** : If you can get a response on the LAN but can't get a response through the router's NAT and it seems to be set correctly, **check the gateway setting is configured properly**.