Case Study: Authenticate command mail by PGP/GPG Authenticate user mode command mail by PGP/GPG. command_mail_restrictions = check_pgp_signature reject Use CLI ( fmlgpg fmlgpgv fmlpgp fmlpgp5 fmlpgpe fmlpgpk fmlpgps fmlpgpv ) to manipulate PGP/GPG keys. Example: generate key for mailing list "ML_NAME". % fmlpgp --command-mail-auth ML_NAME -kg See for more details. Authenticate admin command mail by PGP/GPG. admin_command_mail_restrictions = check_pgp_signature reject Use CLI ( fmlgpg fmlgpgv fmlpgp fmlpgp5 fmlpgpe fmlpgpk fmlpgps fmlpgpv ) to manipulate PGP/GPG keys. Example: generate key for mailing list "ML_NAME". % fmlpgp --admin-command-mail-auth ML_NAME -kg See for more details.