1 example for apt-key
# your_comment_here
# downloads a key via port 80 in case you're firewalled restrictively:
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys $KEYID
# your_comment_here
# downloads a key via port 80 in case you're firewalled restrictively:
sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys $KEYID