If after doing
yum install you get the error:
no package ... is available while you’re absolutely sure that the package you want to install is available in connected repositories, chances are that it is excluded in
My error was
no package ftp is available. This happened because DirectAdmin excluded everything *ftp* presumably to avoid conflicts with the FTP daemon it takes care of, and ftp, the standard unix FTP client, hadn’t been initially installed on the server.