spfquery: 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 CentOS possible default full paths are:

/usr/share/doc/perl-Mail-SPF-2.8.0/bin/spfquery - from package: perl-Mail-SPF
/usr/bin/spfquery - from package: python-pyspf

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