hping: 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/sbin/hping - from package: hping3

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

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