Ubuntu 22.04 The sec_krb5_krb5i_krb5p option should be enabled for all NFS mounts in /etc/fstab. /etc/fstab ^\s*\[?[\.\w:-]+\]?[:=][/\w-]+\s+[/\w\\-]+\s+nfs[4]?\s+(.*)$ 0 ^.*sec=krb5:krb5i:krb5p.*$