How to fix ERR_UNSAFE_PORT error on Chrome when browsing to unsafe ports
On Windows:
Right Click on Chrome shortcut >> Properties >>
Then Append
--explicitly-allowed-ports=xxx to shortcut target
Example:
C:\Documents and Settings\User\Local Settings\Application Data\Google\Chrome\Application\chrome.exe --explicitly-allowed-ports=6666
Resource from here
You may be able to turn this off in Google Chrome, but you do so at your own risk. There is actually a good security reason why Chrome blocks these ports: Basically you open your browser up to being an open proxy for attackers to use to attack other services on your network.
For more information: Why does Chrome consider some ports unsafe?
On Mac you can create an app launching Chrome with parameters mentioned in other answers using Automator built-in Apple application:
Launch Automator
As "Type of document" choose "Application"
Add action "Run shell script"
Replace placeholder
catscript in this action with:
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --explicitly-allowed-ports=5000,6000,7000
Save the created app as something like "Google Chrome with allowed unsafe ports" in your Application folder
Use this new app instead of Google Chrome directly
(optional) Replace default icon of the created "app" - Automator's robot - with Chrome's using this method (note: upvote that answer if you like it!)
Source: http://cubewot.de/node/266
