RSlinx Remote to 1768-enbt

[Ron G 0]

Ok, here's the situation. I have a customer that has one of our machines in another state. I am trying to remotely connect to the machine over the Internet. I am using the Remote Devices via Linx Gateway driver, trying to connect to a 1768-ENBT ethernet card on a compactlogix rack. I have used this driver for connecting to other machines in a similar manner. In fact, I can view a few machines around the globe with my current setup (This tells me that my local computer is capable of connecting). The customer has a simple peer to peer network behind a Linksys WRT54G router. I asked them to setup port forwarding on ports 2222 and 44818. This has been done. The IT guy can remote desktop into a machine on the network and from there, he was able to enter the local IP address of my ethernet card, 192.168.1.130 in a browser window. He was able to pull up the web page from the ethernet card showing its configuration. Using remote desktop to his machine (Yup, remote connecting to a machine that has a remote connection, ain't the Internet great?), I was able to see for myself that the ethernet card is setup properly, as well as the port forwarding on the router. The gateway on their router is 192.168.1.1. For some reason, I seem to recall hearing that using x.x.1.1 can cause issues with RSLinx. However, I can find no mention of this anywhere on the internet. I also checked with AB on this, they have no record of that being an issue for remote connections either. Anyone hear anything like that? On other customers' machines, after doing this, I enter the IP address of the customer in the RSLinx configure driver, Server's IP address or hostname. On the Configure Browser tag, I also enter the IP address of the ethernet card on the customer's netowrk. I did this for this machine and I see the message along the top of the RSLynx window "Browsing - Node 69.183.xxx.xxx not found (I editedt the IP for privacy). My next step is to ping the customer. I try to ping the IP address I was given, and no response. However, if I ping the specific ports, 2222 or 44818, I get a response back. To me, that says the machine is online, but somehow the router is not allowing me to connect. I contacted Rockwell, and they say that I have everything setup fine on my end, it must be a remote issue. I contacted the customer's outside IT guy and he has no experience setting up remote connections for Rockwell software. He spent a few minutes trying to explain to me how we should provide the customer with a full copy of RSLogix5000 so that they can perform the troubleshooting themselves, or that AB should provide a copy for free with every processor. This should tell you all you need to know about his past experience with Rockwell and AB <LOL>. Has anyone else experienced this issue where you can ping the machine, but cannot connect? Oh, I also am running RSLinx version 2.53, if anyone asks. Thanks in advance for any help anyone can provide. This one has me stumped. Ron

[BobLfoot 302]

Only internally on my LAN, I was a PLC 5 with ethernet sidecar. We could ping the sidecar but not connect to the PLC with Linx or Logix. Problem was a bad bus connection between the sidecar and plc5. ended up replacing the multipin connector to resolve.

[paulengr 44]

I'm not sure this makes sense. You can't "ping a port". The ping protocol uses ICMP which doesn't have ports. ICMP is not TCP and it's not UDP. It's a separate protocol. Actually ICMP is intended as a low level protocol that operates in parallel with the IP protocol but it rides encapsulated inside standard IP packets to simplify packet handling. http://en.wikipedia.org/wiki/Internet_Cont...essage_Protocol

[BobLfoot 302]

Might be his Linksys router making him think he can ping a port Paul. Just tested pinging 192.168.2.1:7778 my router ip from the lan side and the Linksys converted it to a 92.242.xx.yy IP and attempted to ping it.

[Ron G 0]

That is exactly what I did, ping xxx.xxx.xxx.xxx:44818. I got a response, where simply pinging xxx.xxx.xxx.xxx gave me no response. Silly me, I was under the impression that this worked in a similar manner to entering the ip address and port number in a web browser. So, I am not really getting a response then? Argh. Thanks for the responses folks Ron

[Eddie Willers 2]

The local IT guy's demonstration of a local PC's ability to connect with the controller via HTTP is encouraging but not determinant. Can you access the controller via HTTP if Port 80 is (very temporarily) forwarded to the controller ? I don't use the Remote Devices Via Linx Gateway (though I know some people do), but rather the ordinary RSLinx Ethernet Devices driver. Sometimes it can be something simple like the -ENBT module lacking the proper Default Gateway address so that it knows how to respond to a packet that comes from outside the local subnet (unlike that HTTP request the local guy showed you). I very strongly prefer VPN over Port Forwarding for a permanent installation. When RSLinx Classic is browsing an "Ethernet Devices" device for the first time, it tries first to connect on Port 2222 (the old CSPv4 protocol). After it gets three "Port Closed" responses, it switches to Port 44818 (EtherNet/IP). In RSLinx Classic's Ethernet Devices driver, you can append ":EIP" to the hostname/IP address to make RSLinx skip the attempt to connect using Port 2222. Some firewalls consider that to be a "port scan" and will block the second and third "port closed" responses that RSLinx needs to see. If you're feeling hacker-y, download NMAP and try using that to probe the router.

[Ron G 0]

Hmmm, never used NMAP before. Nice tool. turns out that the ports are still closed, even though he setup Port Forwarding. Now that I know the ports are showing as closed from the outside, I did some research. It looks like there is a second setting in the WRT54G router that blocks all anonymous Internet Requests. If that box is still checked, the router will not respond. I will see what happens when their IT gets back to me. Thanks for all your help

[Ron G 0]

OK, just got off with the IT guy. Explained that I am NOT seeing the ports open. He went into the settings of the router and sure enough, the Anonymous Internet Request box was checked. He unchecked it, and I could now see port 2222, but not 44818. Checking further, we found that he had set port forwarding on 44218, not 44818. Silly typo. Looks like we had multiple issues going here. Once he set port forwarding on 44818, I can connect to my machine. Thanks for everyon'e help. Ron Edited 5 Jun 2009 by Ron G

[BobLfoot 302]

Tou're Welcome Ron and Welcome aboard mrplc.com.