RSLinx on multiple networks

kalell

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Join Date
May 2014
Location
texas
Posts
6
I have the following scenario and am looking for a little guidance. Computer IP 137.32.54.40 goes to a router WAN 137.32.54.12. LAN is 192.168.248.90 and my controllogix is 192.168.248.91, sub 255.255.255.0, gateway 192.168.248.90. I have opened ports 44818 and 2222 TCP and UDP. I set up an alias of 137.32.54.27 and NAT it to 192.168.248.91. I can TCPing the 137.32.54.27 from computer and if I go to web browser and type in the 137.32.54.27 I connect to the AB product and can see its information. I cannot get RSLinx to locate it though. Says unrecognized device. I have tried Ethernet and put :EIP after 137.32.54.27 and also tried 192.168.248.91 with :EIP on it as well. Any thoughts?
 
welcome to the site
is the version of RSLinx up date - it sounds like you are missing the EDS files
 
If you connect your computer on the LAN side, will RSLinx locate the PLC?
If RSLinx works from the LAN side, you know you have your Rockwell software all set up and working and then you can attack this as a routing issue.

So assuming it does work on the LAN side, I believe RSLinx needs multicasting for its discovery protocol - there are others on this forum that can verify that for sure.

If your troubleshooting indicates the problem is the router, I notice you have connected to your WAN. Could you instead setup a VLAN for your outside network (connect your outside network to a LAN port on its own VLAN)? There are provisions on many routers to allow multicasting to cross VLANs.
 
If I connect to the lan I can see everything like I should. I am not sure doing a VLAN is possible or not. It is RAM 6021 router.
 
Since it does work on the LAN side, I think multicast blocking on the WAN port is likely the culprit.

I've not used this Sixnet/Red Lion router. Looks like a nice product. A quick perusal through the manual does mention multicast traffic. Take a look at the GRE tunneling for multicast and try setting that up. Good luck.
 
RSLinx Classic Version 2.57 is a few years out of date. I like to use the last revision of the 2.5x family (2.59) unless I have a need for the v3.x product.

But that's probably not the problem.

As I understand your post, you're trying to access a ControlLogix from the WAN side of a Red Lion RAM 6021 router.

Your description of adding the ":EIP" suffix to the IP address of the ControlLogix suggests that you are using the Ethernet Devices driver, not the EtherNet/IP driver. That's good; as nwboson noted, the EtherNet/IP driver uses an IP Broadcast for device discovery, while the Ethernet Devices driver uses direct TCP connections.

Let's pursue making the NAT connection work.

We already know that the NAT connection works on TCP Port 80, because you can use a web browser to see the ControlLogix embedded web page.

You mentioned that TCPing (an awesome utility) works with the NAT connection. Did you TCPing TCP port 44818, port 2222, or both ?

When you see the "Unrecognized Device" icon in the RSWho browse, is it just a yellow question mark or does it eventually turn into a yellow question mark with a red X ?

The yellow question mark can be an EDS file issue or other software identity problem, while the red X indicates that the device isn't responding at all.
 
Ken
I tcping 137.32.54.27 44818 and get no responce but as you said it does work on port 80. I have opened the ports in the router but maybe i have something wrong. The question mark ends up with the red X on it.
 
I've posted on this topic in the past but I'll see if I can write a simple summary of how RSLinx Classic uses TCP Ports 2222 and 44818.

TCP Port 2222 was used by the old A-B "CSPv4" Ethernet protocol for the PLC-5E and early SLC-5/05 controllers.

TCP Port 44818 is used by the EtherNet/IP protocol used by all ControlLogix family controllers and all the MicroLogix controllers. Modern (10 years or less) PLC-5E and SLC-5/05 controllers support both protocols.

When the RSLinx Classic "Ethernet Devices" driver starts to browse its list of IP hosts, it first has to determine if the device uses CSPv4 or EtherNet/IP.

If you have added the ":EIP" suffix to the host IP address in the IP host table, RSLinx knows that the device uses EtherNet/IP and goes directly to creating a TCP connection on TCP Port 44818.

If there's no ":EIP" suffix, RSLinx has to probe the device to figure out what it is.

So it starts by requesting a connection on TCP Port 2222. If it gets a connection, it proceeds to interrogate the device ID and shows it in the RSWho browse.

If it gets a "connection refused" answer on TCP Port 2222, it tries two more times then switches to attempting a connection on TCP Port 44818.

Here's the trickiest part: there's a difference between a "connection refused" answer from a device and just a timeout where the device doesn't answer.

RSLinx Classic needs to see three "Connection Refused" answers from TCP Connection requests on TCP Port 2222 before it will automatically switch over from CSPv4 to EtherNet/IP.

[Insert Saint Peter joke here.]

Some routers and firewalls will allow through the first TCP Connection request and will monitor the fact that the device sent a "Connection Refused" answer.

When they get the second request... they consider it to be a TCP Probe attack and block the response. RSLinx Classic gets one response and two timeouts, so it declares a timeout instead of attempting to connect to TCP Port 44818.
 
Thanks for that info !

I'm not sure what "opened the ports" means in this context, nor have I used this router before.

In general, you want to focus on any TCP-port related settings for the NAT connection to be sure that Port 44818 can get through from the WAN to the LAN via that NAT definition.
 
I have attached screen shots of port allow and port forwarf as well as firewall rules. May or may not help...

sshot-2014-05-14-[1].jpg sshot-2014-05-14-[2].jpg sshot-2014-05-14-[3].jpg
 

Attachments

  • firewall rule.txt
    10.5 KB · Views: 44
I see three problems:
1) That third port forwarding rule should be deleted. Your are forwarding one IP port from your WAN ethernet port to a device on the LAN: the fourth rule is all you need to forward 44818 from WAN to your LAN device.
2) I don't think you want that one-to-one NAT. That is usually for mapping a WAN address directly to a LAN address - implies you have multiple WAN addresses.
3) Your WAN addresses are not in the private IP address range of 10.x.x.x, 192.168.x.x, or 172.16-31.x.x. Highly suspicious but probably nothing you can do about it. But curious why an IT person would have set up your network with invalid IP addresses...

Try your tcping to 44818 after fixing items 1 and 2. Good luck

Oh yeah, you also might need to create a firewall rule if the item 1) port forward does not open the firewall automatically. Some routers do, some don't.
 
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