keith@E5570:~$ sudo apt install postfix
[sudo] password for keith:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package postfix is not available, but is referred to by another package.
This ...
keith@E5570:~$ sudo apt install postfix
[sudo] password for keith:
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package postfix is not available, but is referred to by another package.
This ...