title: in centos7, how can i add a zone for localhost and then add an accepted port permanently?
body: <p>The new firewall-cmd command seems to have the public interface automatically a member of the 'public' zone.  The localhost interface is not really a member of the public zone concept, and it seems appropriate that lo is not a member of this default zone.</p>
  
  <p>I would like to ensure that memcached is available on localhost.  We have some customers that zealously set their default policies to DROP, and if my service has a port registered in the firewall, they are ok with that.  But I must register it during installation.</p>
  
  <p>There must either be some way to add localhost as an interface to its own zone, or, perhaps more likely, I do not understand a key concept of this new zone based firewall system.  Thanks.</p>