I'm noob and i got stuck again=(. Here's the problem: i want to install gentoo-linux on qemu virtual machine and i can't connect to internet from vm. So far i found out how to create a necessary hdd image and boot vm from cd iso image. i use last system rescue cd image since it uses gentoo.

I was digging in different manuals about qemu networking, it is said that by default vm is connected to virtual dhcp server of address that blocks all incoming connections. To use fully functional network without necessity of port redirection (this is what i want) it is recomended to modify /etc/qemu-ifup and /etc/qemu-ifdown scripts
(forum rules do not allow me to give direct link to manual i was reading)
I tried this but the only result was that my eth0 got down.

Can anyone help with setting up network on qemu? may be there is some simple way. Or may be i must change something in /etc/qemu-ifup and /etc/qemu-ifdown according to my system parameters?

May be there is some good source of knowledge to understand better how networks are configured in linux?