smtpfront-echo: 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

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/sbin/smtpfront-echo - from package: mailfront

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