Douglas Tarr

How to Allow Unsafe Ports in Chrome

In Chrome, if you attempt to access a website on some non-standard ports, such as port 87, you will see:

"This webpage is unavailable" and the text of your error will be:

Error 312 (net::ERR_UNSAFE_PORT): Unknown error.

To fix this, you have to explicitly allow the unsafe port when you start up chrome.  

Right click on your chrome icon that you use to launch chrome, and click properties.

The textbox that says "Target" will look something like this (your username obviously)
C:\Users\dougt\AppData\Local\Google\Chrome\Application\chrome.exe

To allow ports 81,84 and 87, change it to:
C:\Users\dougt\AppData\Local\Google\Chrome\Application\chrome.exe –explicitly-allowed-ports=81,84,87

This is different from FireFox, which does this in about:config 

There are many sites (such as this) that describe all the chrome command line switches, but oddly, most of them do not include explicitly-allowed-ports