inetutils-telnet: command not found

Have You tried accessing the binary with the full path?

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/inetutils-telnet - from package: inetutils-telnet

You may install the required package with command apt-get install {package}
Error in other languages:
inetutils-telnet: bevel nie gevind nie
inetutils-telnet: comandă negăsită
inetutils-telnet: comando não encontrado
inetutils-telnet: commande introuvable
inetutils-telnet: command not found
inetutils-telnet: käsku ei ole
inetutils-telnet: không tìm thấy lệnh
inetutils-telnet: komanda nerasta
inetutils-telnet: Kommando nicht gefunden.
inetutils-telnet: kommandot finns inte
inetutils-telnet: komut yok
inetutils-telnet: nie znaleziono polecenia
inetutils-telnet: níor aimsíodh an t-ordú
inetutils-telnet: no se encontró la orden
inetutils-telnet: no s'ha trobat l'ordre
inetutils-telnet: opdracht niet gevonden
inetutils-telnet: parancs nem található
inetutils-telnet: perintah tidak ditemukan
inetutils-telnet: príkaz nenájdený
inetutils-telnet: příkaz nenalezen
inetutils-telnet: команда не найдена
inetutils-telnet: командата не е открита
inetutils-telnet: 命令找不到
inetutils-telnet: コマンドが見つかりません