[CentOS] IP aliases Centos 6.x

What's the right way to assign an IP alias to an ethernet interface
that you want to bring up and down manually, not on boot?

I tried the old way of making an ifcfg-eth3:0 file and it does work
with the ifup, ifdown commands, but even though I specified onboot=no,
it activated at boot-up.

-- 
   Les Mikesell
     lesmikesell at gmail.com