ubuntu@maestro:~$ klist
Credentials cache: FILE:/tmp/krb5cc_1000
        Principal: ubuntu@EXAMPLE.COM

  Issued                Expires               Principal
May 30 14:05:35 2017  May 31 00:05:35 2017  krbtgt/EXAMPLE.COM@EXAMPLE.COM
May 30 14:05:41 2017  May 31 00:05:35 2017  cifs/maestro@EXAMPLE.COM
ubuntu@maestro:~$ smbclient //maestro/ubuntu -k
Domain=[EXAMPLE] OS=[Windows 6.1] Server=[Samba 4.5.8-Ubuntu]
smb: \>