virtualbox: Disable DHCP server for host-only network

Publicat la 24 January 2015 Scrie si tu o vorbulita (1) Comentarii

Recently I decided to install virtualbox headless on my server to have something to play around with. Ok... cool...
The installation went fine, creation couple of VMs also.

Also I wanted to have my DHCP server, controlled by me. So far so good. I installed isc-dhcp-server on host, I configured it just fine... but at some point I realized that there is something wrong in the logs.

Jan 24 02:11:00 server dhcpd: DHCPDISCOVER from 08:00:27:3f:03:fe via vboxnet0
Jan 24 02:11:00 server dhcpd: DHCPOFFER on 192.168.56.253 to 08:00:27:3f:03:fe via vboxnet0
Jan 24 02:11:00 server dhcpd: DHCPREQUEST for 192.168.56.106 (192.168.56.100) from 08:00:27:3f:03:fe via vboxnet0: lease 192.168.56.106 unavailable.

Hmm! Houston we have a problem! After digging a little bit, I discovered that there is rogue DHCP server in my network... At least now I know what I am looking for.
I stopped my DHCP server, I disabled virtualbox DCHP server (from phpvirtualbox... I know, I was lazy) and my VM was still getting IP address... Something is fishy here. Ok, then maybe something is wrong with phpvirtualbox! I decided not to trust GUIs, so I started with to play around with cli commands:

[codesyntax lang="bash"]

vboxmanage list dhcpservers

[/codesyntax]
NetworkName:    HostInterfaceNetworking-vboxnet0
IP:             192.168.56.100
NetworkMask:    255.255.255.0
lowerIPAddress: 192.168.56.101
upperIPAddress: 192.168.56.254
Enabled:        No

Note: And this was the output after disabling the DHCP server from phpvirtualbox.

No problem...

[codesyntax lang="bash"]

vboxmanage dhcpserver modify --netname HostInterfaceNetworking-vboxnet0 --disable
vboxmanage list dhcpservers

Ok... I checked it one more time...
[codesyntax lang="bash"]

ifdown eth1 && ifup eth1

[/codesyntax]

The VM received the same IP address! This is going to be though, I said to myself...

[codesyntax lang="bash"]

VBoxManage dhcpserver remove --netname HostInterfaceNetworking-vboxnet0

[/codesyntax]

And now, when I listed the dhcpservers the above command returned nothing.

Perfect... I checked it again:

[codesyntax lang="bash"]

ifdown eth1 && ifup eth0

[/codesyntax]

Still got the IP... Fuck!!!

Ok... This is my personal server, is not in production, I can afford to reboot it... (Please notice that I was lazy again... I could remove and add back the virtualbox kernel modules)

Guess what?! After rebooting my VM was able to get the right IP address from my DHCP server!