rlogin: 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/kerberos/bin/rlogin - from package: krb5-appl-clients
/usr/bin/rlogin - from package: rsh

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

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