Accessing Siemens S7-1200 webserver over router

When the S7-1200 has an IP adress assigned on the local network it can be accessed trought that address. I don’t think people who are able to program the PLC will have difficulties with that.

When the PLC needs to be accessible over a router making it possible to browse to the web interface from everywhere on the internet there are some settings in the router and the PLC that need to be correct.

On the router a NAT row needs to be added to forward port 80 and 443 to the PLC address. Port 80 is for the http pages port 443 is needed to access secure pages over https.

In the PLC it is absolutely required to set the router IP address. When this isn’t set the webserver the  S7-1200 PLC will be accessible over the local network but not over the router.

Don’t forget to change the password of the PLC. Allowing access to the PLc over internet can be usefull but also very dangerous when not secure.

Also it’s not recommended to enable the webserver on a S7-1200 PLC if it’s not necessary. A DOS (Denial Of Service) attack can make the PLC crash!