The certutil command with the -L (list) an -d (directory) options can be used to list the certificates in the nssdb (Network Security Services Database). In this example, there are no certificates in the nssdb.

~]# certutil -L -d /etc/pki/nssdb

Certificate Nickname                        Trust Attributes
                                            SSL,S/MIME,JAR/XPI

The certutil command with the -A (append), -n (name) -t (type) -d (directory) and -i (file) options can be used to append certificates to the nssdb (Network Security Services Database).

~]# certutil -A -d /etc/pki/nssdb -t "TC,," -n "*.example.com root CA" -i root.pem
~]# certutil -A -d /etc/pki/nssdb -t "TC,," -n "*.example.com intermediate CA" -i intermediate.pem
~]# certutil -A -d /etc/pki/nssdb -t "TC,," -n "*.example.com" -i server.pem

Let's check the nssdb again. Notice there are entries for the root, intermediate and server certificates.

~]# certutil -L -d /etc/pki/nssdb

Certificate Nickname                        Trust Attributes
                                            SSL,S/MIME,JAR/XPI

*.example.com root CA                    CT,,
*.example.com intermediate CA            CT,,
*.example.com                            CT,,