virtualbox.org

I'm running virtual box on my notebook..
When the notebook is plugged in my home network, I use my guest with bridged interface. When the notebook is disconnected, I use my guest with host-only adapter (because bridged adapter fail since the interface is down).
I was attempting to give ip to my guest based on the interface it was attached, but host-only adapter has an hidden useless DHCP that turn my own host DHCP server useless. How can I turn it off?

Why would you do that? The DHCP server will give you an IP which will allow it to communicate with the host only adapter in the host. That is what host only does. Check the IP of the host only adapter from the host OS. The IP in the vm has to be in the same subnet as that.

Because it is easier to have a DHCP server leasing ips to my guest and don't having to bother with different ip configurations from bridged (10.1.1.0) to host-only (192.168.56.0).. And besides that, sometimes I use host-only networked guest to access the Internet using my host as router.. (to don't have to turn off the guest to switch from host-only to bridged)..

But your guest will not get an IP from your LAN router if it is set to host only!

If you want your guest to always have the same IP, use static config. It will then ignore DHCP completely.