Install iftop on CentOS or RedHat (RHEL)

Visit following web site and check what is latest version of iftop

   http://pkgs.repoforge.org/iftop/


Get iftop package.
  wget http://pkgs.repoforge.org/iftop/iftop-1.0-0.pre3.el7.rf.x86_64.rpm

Install iftop by rpm tools
  rpm -ivh iftop-1.0-0.pre3.el7.rf.x86_64.rpm