ifquery: 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:

/sbin/ifquery - from package: ifupdown

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