To configure GnuPG to use keys.openpgp.org as keyserver, add this line to your gpg.conf file:
keyserver hkps://keys.openpgp.org
To locate the key of a user, by email address:
gpg --auto-key-locate keyserver --locate-keys user@example.net
To refresh all your keys (e.g. new revocation certificates and subkeys):
gpg --refresh-keys
Keys can be uploaded with GnuPG's --send-keys command, but identity information can't be verified that way to make the key searchable by email address (what does this mean?).
You can try this shortcut for uploading your key, which outputs a direct link to the verification page:
gpg --export your_address@example.net | curl -T - http://localhost:8080
Alternatively, you can export them to a file and select that file in the upload page:
gpg --export your_address@example.net > my_key.pub
Some old ~/gnupg/dirmngr.conf files contain a line like this:
hkp-cacert ~/.gnupg/sks-keyservers.netCA.pem
This configuration is no longer necessary, but prevents regular certificates from working. It is recommended to simply remove this line from the configuration.
While refreshing keys, you may see errors like the following:
gpg: key A2604867523C7ED8: no user ID
This is a known problem in GnuPG. We are working with the GnuPG team to resolve this issue.
For users who want to be extra careful, keys.openpgp.org can be reached anonymously as an onion service. If you have Tor installed, use the following configuration:
keyserver hkp://zkaan2xfbuxia2wpf7ofnkbz6r5zdbbvxbunvp5g2iebopbfc4iqmbad.onion
Background image retrieved from Subtle Patterns under CC BY-SA 3.0