apt-key Behind Proxy

To run apt-key in Ubuntu behind proxy, you can pass an argument: --keyserver-options http-proxy=http://<proxy_url>:<port> to apt-key command.

For example:

sudo apt-key adv --keyserver-options http-proxy=http://cache.itb.ac.id:8080/ --keyserver keyserver.ubuntu.com --recv-keys 00A6F0A3C300EE8C