Preventing someone else's ip capture (DHCP and Ubuntu Server)?

M

Marat Rakhmatullin2011-01-21 12:58:33

DHCP

Marat Rakhmatullin, 2011-01-21 12:58:33

The question is simple, but unfortunately I am not a Linux user.

After reboot, the server grabs someone else's ip-address (10.1.8.44)

If you write:
sudo /etc/init.d/networking restart
then everything falls into place: the server takes a free ip

in /etc/network/interfaces only this:

# The loopback network interface<br/>
auto lo<br/>
iface lo inet loopback<br/>
<br/>
# The primary network interface<br/>
auto eth0<br/>
iface eth0 inet dhcp

Where to add something so that the server immediately takes a free ip-address?

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6 answer(s)

M

merlin-vrn, 2011-01-21
@Stranger

On the client in the files /var/lib/dhcp3/dhclient.eth?.leases what? It just stores the address that was “issued before” and which you can ask the server again (there is such a possibility in the DHCP protocol). Perhaps Ubuntu is trying to do this and doing it wrong, or the server is not according to the standard and does not understand it.
If anything, these files can be safely deleted.

V

Vladimir Zhurkin, 2011-01-21
@icCE

Generally a strange problem and I'm not entirely sure if ubuntu is to blame.
As an option, register the permanent address of the machine on DHCP.

M

merlin-vrn, 2011-01-22
@merlin-vrn

Read section 3.2 of RFC 2131 on how DHCP works. There, as a result, the client is required to check that there will be no conflicts before final installation of the configuration (send an ARP request). If he ends up with a conflicting address, then the client is to blame.
Ubuntu uses dhclient. It might be worth reading more about it. If you want to try alternatives, then these are udhcpc, dhcpcd; I have no idea how to install them in Ubuntu.

M

Marat Rakhmatullin, 2011-01-21
@Stranger

Thank you!

C

Carzil, 2011-01-21
@Carzil

And what will be the name? MedvYandex? DamGoogle?

M

Marat Rakhmatullin, 2011-01-22
@Stranger

I think I figured out who is to blame:
This conflicting address (10.1.8.44) now has a widescreen plotter that sleeps most of the time (it can oversleep, taking into account the days off 3-4), waking up, it most likely does not bother to ask dhcp- servers, and if they gave his address to someone ... and he himself can’t print normally and powders the brains of others ... But I’ll still watch him (and a couple of his brothers), this happens regularly on our network, networkers dismiss it (“ sometimes, just disable and enable the connection"), I think we will require statics for all network printers, the computers of which are also "turned off" into hibernation.