I have problem, I just started with servers, so I don't have a lot of experience and I have problem which I can't solve myself.

Important: I'm doing everything on virtual machines: VMware Workstation 12 Player !

I have running DHCP server on openSUSE Linux Enterprise 11, which is configured to give everyone IP from to
Server is running good, DHCP have the same IP of SUSE Linux.
Network Card in my settings of Virtual Machine I have configured to NAT, and it's eth0 card. (DHCP is also working on eth0 card)

I installed Debian 8.2 on another Virtual Machine, and I'm trying to set it up so that SUSE can assign IP from xxx.xxx.xxx.20 to xxx.xxx.xxx.100

Well, unfortunately, for now I'm stuck. Debian always gets the same IP adress from DHCP server others than mine. Debian also has NAT and eth0 card.

Debian has dhcp-client package, and after configured it, system gets the same IP adress...
Debian gets

Once I managed to somehow "fix" DHCP client on Debian, and got first adress from the pool (
I don't know how I managed to "fix" it, but I wrote the following commands:
- dhclient eth0
- ifup eth0
- ifdown eth0
- ifup eth0

Then I realized, that my Debian got IP adress from my DHCP Server !

Unfortunately, I've done that just for one time.

What am I doing wrong?

Please help me.

P.S: Sorry for my english, I'm not native speaker in that language.