Пакет krb5-kdc недоступен [дубликат]

Ubuntu Server 18.04 { {1}} Попытка:

~$ sudo apt-get update
Hit:1 http://archive.ubuntu.com/ubuntu bionic InRelease
Get:2 http://archive.ubuntu.com/ubuntu bionic-security InRelease [83.2 kB]
Get:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease [88.7 kB]
Get:4 http://archive.ubuntu.com/ubuntu bionic/main Translation-en [516 kB]
Get:5 http://archive.ubuntu.com/ubuntu bionic-security/main Translation-en [78.1 kB]
Get:6 http://archive.ubuntu.com/ubuntu bionic-updates/main Translation-en [161 kB]
Fetched 927 kB in 1s (628 kB/s)
Reading package lists... Done

:~$ sudo apt-get install krb5-kdc krb5-admin-server
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package krb5-kdc is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'krb5-kdc' has no installation candidate
E: Unable to locate package krb5-admin-server

В документации Ubuntu:

sudo apt install krb5-kdc krb5-admin-server

Тот же результат.

Был старый пост об Ubuntu 14 ... обновление решило его проблему, а не мою.