How to access a Siemens PLC from internet

PLC (Programmable Logic Controllers) Siemens
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While it is possible to connect a PLC to the internet, it represents a significant security threat.

Let me repeat: Do not do this. When you connect a PLC (or any device) to the internet, it means that device is available to anyone and everyone in the world. Do not do this.

You might have many ideas about why I am wrong. For example:

  1. Noone is going to know that I am connecting this – The “bad guys” are scanning the internet on a regular basis. Using the right tools, the entire internet can be scanned in a few hours (or less). If you open a port and leave it open for more than a day, there is a good chance that someone will find your open port.

  2. A Siemens PLC is a specialized, relatively unknown device – No, you are wrong. PLCs are a very well known device. Port 102, for example, is the one used by the S7 PLC.

  3. Noone is going to bother with my PLC – Maybe not today, maybe not tomorrow. But I can guarantee that within a month or two, your PLC will be discovered.

To Repeat: Do not connect any device to the internet without understanding (and taking the proper measures) to protect that device. A PLC has no protection against malicious (or even accidental) connections and operations.