has to be used in order to change your PDC password (which actually is your Kerberos password for the realm NADA.KTH.SE). You should (if possible) execute this command on your own local computer. For this to work you need to have some Kerberos software installed (for instance MIT Kerberos or Heimdal).
If you are using the Heimdal software the kpasswd command is usually located in:
Please make sure that your local computer is NOT behind some firewall or NAT when changing your password, that will not work.
Instead, you could then login at PDC and change your password. Please note that you might need to load the Kerberos software at PDC before using kpasswd:
module add heimdal
Your password is stored on several Kerberos servers, one being the master server. Password updates propagate from the master to the backup servers once an hour. Hence, it might take up to one hour for your new password to become effective on all machines.
Side note: unfortunately there are other password-changing commands (like "passwd" and "yppasswd") available on various of our machines. These commands do not change your Kerberos password and hence they are of no use to you.