Ethernet Remote Access Headache

[George Graziano]

My work laptop with all the PLC software on it, has 2 ethernet cards. The internal one and an USB to ethernat as a second one. When problems at work, I goto www.logmein.com and I can get to anything connected to that computer. My on board ethernet is on my PLC network. My USB to ethernet is on my company ethernet. I have never had a problem talking to a PLC on the PLC network.

 

[ndzied1]

How do you guys handle PLC that's located on private network that's not connected to the Internet?

I believe there are two ways without an internet connection. One is to use a good old fashioned analog phone line and modems. This is slow and depends on there being analog lines where you need them.

There other way is to use a GSM modem. This is the same technology in your cell phone but used as a modem. This requires the modem and a monthly data plan. A variation of this is with a computer local to the machine with the required programming software theathered to a smart phone for internet access. I have used this with teamviewer. Of course, this method depends on there being somewhat stable cellular service where the machine is.

 

[The Plc Kid]

@Bill Robinson

It makes no difference how the machine connects to the internet wireless,cellular,wired LAN. To logmein a network connection is a network connection.

Make sure your connection that connects you to the internet is priority 1 here is how you do this.

First opena comand prompt go to run and type cmd

the type in this command netstat -rn |more

This will list all your connections and there priority

If the connection that connects you to the internet is not on top then change it before you install logmein to make things easy ( you can chnage it after LMI is installed but it is a PITA if you don't love windows networking.

 

[The Plc Kid]

The list only populates so far so fron the netstat command you may have to hit enter for more severla times to get back to your prompt

To change the priority type in ncpa.cpl

Find the connection that connects you to the net and change its priority by right clicking on it and chose properties

Then choosr IPV4 as I doubt you're using V6 when IPV4 is highlighted click the properties button

Then click the advanced button from the bottom

Uncheck the automatic metric box and put in the priority number you want msot likely higher than 1 as 1 should be for your loopback adaptor.

I always like to finish this off with a reboot.

Then the machine restatrts open command promt do another netstat and verify that it took and the priority changed then install logmein. Test logmein from the logmein website and see if the machine shows up. if it does then you can connect.

 

[Dravik]

route print
does the same thing btw PLCKID, You can also then use route change to adjust the metric for a given route/interface.

 

[The Plc Kid]

Thanks Dravik

I never knew that way. Nice one to add to the ole toolbox.

Any reason to do it your way other than keeping it all in command prompt and a little faster and easier?

Does your way not require a reboot. Doing it the way I described normally requires a reboot sometimes enable and disable the changed adaptors works but it is a crapshoot IMO.

Your way is easier than mine so I will use that in the future.

Thanks for the tip.

 

[Dravik]

Yeah, using the route command makes the changes instantly.

Plus, I have a lot of systems I have to add/update static routes for, So i prefer the route version so I can push it via scripted GPO.