How to Setup Dogtag CA Server in Linux 9

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In this Linux tutorial, you will learn how to install an in-premises Certificate Authority Server by using Dogtag CA on CentOS/Rocky Linux 9. #centlinux #linux #cryptography

What is a Certificate Authority?:

Certificate Authority (CA) is like a digital security guard for the internet. It issues digital certificates, which are virtual ID cards for websites or online services. These certificates verify the identity of the website and help create a secure connection between your device and the website, ensuring that your information stays safe during online communication.

Common Certificate Authority software includes:

  • Let’s Encrypt: This is a widely used and free certificate authority that helps websites secure their connections.
  • DigiCert: A well-known commercial CA that provides SSL and other digital certificates to enhance online security.
  • Entrust Datacard: This CA offers various digital security solutions, including certificates for websites and online transactions.
  • Comodo CA: Another provider that offers digital certificates and cybersecurity solutions to protect online communications.

Using a Certificate Authority is essential to maintain a secure and trustworthy online environment.

What is Dogtag CA?:

Dogtag Certificate System, commonly referred to as Dogtag CA, is an open-source Certificate Authority (CA) software suite. It provides a set of services for managing and issuing digital certificates within an enterprise or organization. The Dogtag CA is designed to meet the security and certificate management needs of large-scale deployments.

Key features of Dogtag CA include:

  • Certificate Management: It facilitates the issuance, renewal, and revocation of digital certificates, which are crucial for establishing secure communication channels.
  • Key Pair Generation: The system can generate and manage cryptographic key pairs used in the creation of digital certificates.
  • LDAP Integration: Dogtag CA often integrates with LDAP (Lightweight Directory Access Protocol) for efficient and scalable directory services.
  • Smart Card Support: It supports the use of smart cards for enhanced security in authentication and certificate management.
  • Public Key Infrastructure (PKI): Dogtag CA is part of a PKI, which is a framework that manages digital keys and certificates.

Dogtag CA is commonly used in enterprise environments where a robust and secure certificate management system is required. It’s particularly well-suited for organizations that need to manage a large number of digital certificates and ensure the integrity and confidentiality of their communication channels. The open-source nature of Dogtag CA allows for flexibility and customization to meet specific organizational requirements.

Video to Setup Dogtag CA on Linux:

YouTube player

Environment Specification:

We are using a minimal Rocky Linux 9 virtual machine with following specifications.

  • CPU – 3.4 Ghz (2 cores)
  • Memory – 4 GB
  • Storage – 40 GB
  • Operating System – Rocky Linux release 9.2 (Blue Onyx)
  • Hostname –
  • IP Address –

Pre-installation Configuration:

Login to your Rocky Linux Server as a privileged user by using any ssh client.

Set hostname for your Linux machine and configure local DNS resolution as follows.

# hostnamectl set-hostname
# echo ca-server >> /etc/hosts

For Dogtag CA installation, you must increase the maximum number of file descriptors that your system can open at a time.

# vi /etc/security/limits.conf

Add following lines in this file.

# Dogtag CA Settings
root hard nofile 4096
root soft nofile 4096

Update Linux software packages by executing following command.

# dnf update -y

The above command may also update software packages related to Linux Kernel. In such case, reboot your Linux machine before moving forward.

# reboot

Check the Linux OS & Linux Kernel version.

# cat /etc/os-release | grep PRETTY_NAME
PRETTY_NAME="Rocky Linux 9.2 (Blue Onyx)"

# uname -r

Installing Dogtag CA:

Dogtag CA server requires LDAP database for storing certificate and user information. Therefore, you should install LDAP server along with your Certificate Authority software.

# dnf install -y 389-ds-base pki-ca

Create a file ~/instance.cfg to configure LDAP Directory Server (DS) instance.

# vi ~/instance.cfg

Add following lines in this file.

config_version = 2


root_password = Ahmer@1234


sample_entries = yes suffix = dc=ca-server,dc=centlinux,dc=com

You can now use dscreate command with instance.cfg file to create directory server instance.

# dscreate from-file ~/instance.cfg
Starting installation ...
Validate installation settings ...
Create file system structures ...
Create self-signed certificate database ...
Perform SELinux labeling ...
Create database backend: dc=ca-server,dc=centlinux,dc=com ...
Perform post-installation tasks ...
Completed installation for instance: slapd-localhost

Execute pkispawn command to create your Certificate Authority Server.

# pkispawn


    Interactive installation currently only exists for very basic deployments!

    For example, deployments intent upon using advanced features such as:

        * Cloning,
        * Elliptic Curve Cryptography (ECC),
        * External CA,
        * Hardware Security Module (HSM),
        * Subordinate CA,
        * etc.,

    must provide the necessary override parameters in a separate
    configuration file.

    Run 'man pkispawn' for details.

Subsystem (CA/KRA/OCSP/TKS/TPS) [CA]:

  Instance [pki-tomcat]:
  HTTP port [8080]:
  Secure HTTP port [8443]:
  AJP port [8009]:
  Management port [8005]:

  Username [caadmin]:
  Verify password:
  Import certificate (Yes/No) [N]?
  Export certificate to [/root/.dogtag/pki-tomcat/ca_admin.cert]:

Directory Server:
  Hostname []:
  Use a secure LDAPS connection (Yes/No/Quit) [N]?
  LDAP Port [389]:
  Bind DN [cn=Directory Manager]:
  Base DN [o=pki-tomcat-CA]:

Security Domain:
  Name [ Security Domain]:

Begin installation (Yes/No/Quit)? Yes

Installing CA into /var/lib/pki/pki-tomcat.

                                INSTALLATION SUMMARY

      Administrator's username:             caadmin
      Administrator's PKCS #12 file:

      To check the status of the subsystem:
            systemctl status pki-tomcatd@pki-tomcat.service

      To restart the subsystem:
            systemctl restart pki-tomcatd@pki-tomcat.service

      The URL for the subsystem is:

      PKI instances will be enabled upon system boot


Enable, to ensure autostart of Dogtag service.

# systemctl enable
Created symlink /etc/systemd/system/ → /usr/lib/systemd/system/

Reboot your Rocky Linux machine.

# reboot

Post-installation Configuration:

File instance.cfg contains the root password in plain text. Since this file is no longer required, therefore, premanently delete the this file by using shred command.

# shred -u -z ~/instance.cfg

Dogtag CA web interface uses service port 8443/tcp. Therefore, to make your Certificate Autority server accessible across the network, you need to enable this port in your Linux Firewall.

# firewall-cmd --permanent --add-port=8443/tcp

# firewall-cmd --reload

Open URL in a web browser.

Dogtag CA Web UI 1

You will encounter a Certificate Warning in your Web Browser. It is because the SSL certificate of your CA server is self signed and your browser does not see your CA server as trusted.

Click on <ENTER>.

Dogtag CA Web UI 2

Click on <Certificate Authority>.

Dogtag CA Web UI 3

Click on <SSL End Users Services>.

Dogtag CA Web UI 4

Due to the SSL certificate error, your web browser display warnings for SSL agent. To get rid of these warnings, you need to import your root CA certificate in your web browser.

If you are accessing Dogtag Web UI from a Linux machine then you can transfer your root CA certificate by using scp command.

# scp /root/.dogtag/pki-tomcat/ca_admin_cert.p12

For windows machine, you can use an sftp client to transfer root CA certificate to your client. Or in Windows 11, you can use pscp native command to do the same.

> pscp root@ca-server:/root/.dogtag/pki-tomcat/ca_admin_cert.p12 .
root@ca-server's password:
ca_admin_cert.p12         | 2 kB |   2.9 kB/s | ETA: 00:00:00 | 100%

You can now import the root CA certificate in your web browser.

Refresh the Dogtag web user interface.

Dogtag CA Web UI 5

Your in-premises CA server hase been configured successfully.

Read Also: Configure a Certificate Authority in CentOS 7


In this Linux tutorial, you have learned how to configure a in-premises Certificate Authority server on CentOS/Rocky Linux by using Dogtag CA software. We recommend that to understand cryptography. you should read Bulletproof TLS and PKI, Second Edition: Understanding and Deploying SSL/TLS and PKI to Secure Servers and Web Applications 2nd ed. Edition (PAID LINK) by Ivan Ristic.