You may not be able to boot from the DVD, and I simply remind you to change the boot order. You say, "What?" I tell you look in the BIOS. You may say, "What is a BIOS.
This is why Technicians love IPMI/Remote Management. They can even do this with remote access. <$20 extra on top, most servers have it already. Excellent feature to have on your server. All of the ones in the recommended section have it. I believe almost all Dell Servers have it as well. The high and very high end desktops (Q67) in the recommended section have it as well.
It can make life much much easier for a remote installer. Saves you a bit of time too.