kinit: Cannot contact any KDC for realm 'UBUNTU' while getting initial credentials

Solution 1:

[domain_realm]
        .UBUNTU = UBUNTU
         UBUNTU = UBUNTU

keep a register

Solution 2:

Although this is a 2 years old question, I am putting an answer for it, for I had similar problem.

LX-141(root)# root/greg>net ads join -S W12R2-C17.jamie_ad1.net -U Administrator%pwd
kerberos_kinit_password Administrator@JAMIE_AD1.NET failed: Cannot contact any KDC for requested realm
Failed to join domain: failed to connect to AD: Cannot contact any KDC for requested realm

In my case, the result was to re-start the "Kerberos Key Distribution Center" service on the Windows machine, which either was stopped manually by someone or it crashed.

That can be exactly the same issue on the Linux side - unresponsive KDC server.

I hope it will help someone in future.