[CentOS] How to make a network interface come up automatically on link up?

Joakim Ziegler wrote:
> Do I need to disable NetworkManager for everything to make this work?
>
> As I'd mentioned before, the problem isn't that the interface doesn't
> come up on boot, it does, but since it's a point to point interface,
> when I reboot the computer on the other end, it goes down and doesn't
> come back up automatically. That is, link going down and up makes the
> network configuration stay down, I have to manually take the interface
> down and back up to make it work again.
<snip>
Disabling NetworkManager, if you've got a wired connection, is *always* a
Good Idea, IMO. There's *no* reason for it on anything but a mobile
system.

Now - did you say that this was an infiniband connection? We've got one
system like that, and it's ip0. The ifcfg-ib0 we've got is
    DEVICE=ib0
    TYPE=Infiniband
    BOOTPROTO=static
    BROADCAST=192.168.20.255
    IPADDR=192.168.20.1
    NETMASK=255.255.255.0
    NETWORK=192.168.20.0
    ONBOOT=yes

       mark