How to find out if the local server is available?

Question

PHP

In the local network, a server (IIS) 1C was raised
, access to it is implemented via IP, for example 192.168.0.100/Step/en_US
through port forwarding, access to the server from the outside is implemented, respectively, there is already another IP
http://143.xxx.xxx.xxx/ Step/en_US/ on the website of the office they screwed
the 1C authorization form (don't ask why) there was
a problem whether the local server to substitute the desired value when the person is in the office or working remotely tried to write to javascript, but here the browser restriction on cross-domain requests is triggered

Answer 1

why such a bike? normal authorization should not work like this

Answer 2

You can try to do this: find out the IP of the person who visits the page, and if the user came from the local network, then his IP will most likely be local (for example, 192.168.0.12), otherwise it will be global.