Прокси-сервер во FreeBSD отклоняет соединения

Вы можете облегчить себе жизнь, установив command-not-found helper

$ sudo apt install command-not-found
[…]
$ showmount
Command 'showmount' is available in '/sbin/showmount'
The command could not be located because '/sbin' is not included in the PATH environment variable.
This is most likely caused by the lack of administrative priviledges associated with your user account.
showmount: command not found