Is it possible to set a custom URL for captive portal detection in Ubuntu?
Ubuntu uses https://connectivity-check.ubuntu.com by default to check the connection. Is there a way to change this URL, for example to https://your.host.com/another-path?
You can set the URL using the uri parameter in the NetworkManager config file /etc/NetworkManager/NetworkManager.conf. Add the following lines there:
[connectivity]
uri=https://your.host.com/another-path
The important part is that the server must return either the header X-NetworkManager-Status with a value of online or a body content with NetworkManager is online.
You can also set interval to set the check interval in seconds and response to require a specific string in the check response. For more information see the CONNECTIVITY SECTION of the NetworkManager man page.
After that you have to restart the NetworkManager or reboot your system:
# sudo service network-manager restart
