Hello,

Please can someone describe or give a solution (example) for a wireless (mobile) connection between M874 router (with S7-1500 attached) and PC/or Android phone. My SIM card is with dynamic IP but all examples are describing solutions with static IP's.

I want to be able to enter in S7-1500 web server to download log files and looking at PLC status.

I have tried many combinations from the given examples by Siemens but didn't make it work.

Thank you in advance.

PS. If someone made connection with TIA portal please share.

Regards

Kostov

Hello,
If your M874 has a dynamic IP address, you must configure dynDNS client in the M874 and use a DNS name to reach it. But you are dependant on a third party for the name resolution.

To avoid that kind of difficulty, the latest common practice is to have a VPN server at your company location (the company mostly has a fixed IP). The M874 opens a VPN tunnel towards the server, and the IP of the M874 may be dynamic.

The technician abroad also connects with a VPN client to the same server.
The IP address of the VPN client can also be dynamic.

The server is configured to bridge the two tunnels, so that the technician can reach the network behind the M874.

This is explained in this sample here:
Setting up a secure VPN Connection between a Smartphone (Android), SCALANCE S615 and SINEMA Remote Connect Server
https://support.industry.siemens.com/cs/us/en/view/109479641

The S615 can be replace here by a M874 (the M874 can be seen as a S615 with a wireless interface).

An example with an Ios Tablet

An example with a PC where you could run TIA.

Advantage of having a central server is the central management of the VPN settings.
For the case that you have this situation several times (you want to support several remote locations).

Hi  jklm,

Thank you for the comprehensive response. I was going to clarify my situation and it is that i am using Alcatel wireless hotspot router with SIM card as well  to connect my PC to internet so .. dynamic IP also on the PC side. I am using this PC in a place where i don't have internet access except via that Alcatel router.

As i understand this is not big deal as long as i use my private VPN server that i can set in my office (i believe Windows has such option or you can suggest a VPN software in particular?) where indeed we have static IP.

About the option with DDNS service. I was trying to make M874 a VPN server with NO-IP option while using the free service of NOIPdotCOM where i can put the address they gave me in the M874 settings.

But on the client side (my PC) i was using only SOFTNET Security Client v4 as option and didn't have any success on that. Again to clarify that i didn't find a specific manual for that but took directions from here and there.

As i understand the PC and M874 will be both clients?

What will happen if my server dies for a few hours? Will M874 connect again afterwards automatically?

Now when you see the whole picture do you know other way of connecting my PC and the M874 or VPN is the only solution for now?

Thank you

Regards

Kostov 

Hello,
To make your M874 a VPN Server, there is another potential problem. It must be reachable on Internet for incoming requests. This means that it must have a public IP address (else it is not visible/reachable on Internet). Many wireless operators, due to the lack of public IPv4 addresses, uses a NAT router in their infrastructure, and assign a private IP address to standard SIM contracts.
Having a private IP is not an issue when you act as client (outgoing initiative) because the operator will NAT your questions. But accepting incoming is problematic.
Even if you get a public IP for the M874 to day, my feeling is that on a long term the trend is to NAT at the operator side. And the risk could be that it would work now, but for how long in the future.

Large customers can buy a so called private APN, which means that the operator is building a private network (closed user group) in his infrastructure for the customer. The systems can get than a fixed private IP that is reachable in the private APN.

So, unless you setup a private APN network, we fall back to the central server solution for a long term solution.
In that scenario, the only point that must be able to accept incoming traffic is the server.
The M874 and the remote PC can have a dynamic IP.
The M874 can be setup to have a permanent tunnel (tries to reconnect till server is back), or via a contact input on the M874 (= on demand).

Thank you

Best regards

Kostov