Kerberos Server Installation

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In this tutorial I will show you how to install Kerberos server on Ubuntu 16.04.

sudo apt install krb5-kdc krb5-admin-server krb5-config -y

Enter your realm. I will use REALM.CA

Enter your servers. I will use localhost

Enter your administrative server. I will use localhost

Now you can click Ok and installation will continue.

Next we can create our new realm

sudo krb5_newrealm

Enter your password then confirm it.

Now we can edit our kadm5.acl to have admin. Uncomment “*/admin *”

sudo nano /etc/krb5kdc/kadm5.acl

Now we make our keytabs directory and grant the necessary permissions.

sudo mkdir -p /etc/security/keytabs/
sudo chown root:hduser /etc/security/keytabs
sudo chmod 750 /etc/security/keytabs

Now we edit our krb5.conf file

sudo nano /etc/krb5.conf

Ensure it looks like the below

[libdefaults]
        default_realm = REALM.CA
 
 
[realms]
        REALM.CA = {
                kdc = localhost
                admin_server = localhost
        }
 
 
[domain_realm]
        .realm.ca = REALM.CA
        realm.ca = REALM.CA

Now we can restart the kerberos services

sudo service krb5-kdc restart; service krb5-admin-server restart

Once you create a principal if when you attempt to use kadmin you get the error “GSS-API (or Kerberos) error while initializing kadmin interface”. Then do the following.

sudo RUNLEVEL=1 apt-get install rng-tools
cat /dev/random | rngtest -c 1000
sudo apt-get install haveged
cat /proc/sys/kernel/random/entropy_avail
cat /dev/random | rngtest -c 1000
haveged -n 2g -f - | dd of=/dev/null

Uninstallation

sudo apt remove --purge krb5-kdc krb5-admin-server krb5-config -y
sudo rm -rf /var/lib/krb5kdc

References
I used the following references as a guide.

http://blog.ruanbekker.com/blog/2017/10/18/setup-kerberos-server-and-client-on-ubuntu/ 
http://csetutorials.com/setup-kerberos-ubuntu.html