jdns: command not found

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 CentOS possible default full paths are:

/usr/bin/jdns - from package: qjdns

You may install the required package with command yum install {package}

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