[pkg-dhcp-devel] Bug#703691: isc-dhcp-client: In some conditions dhclient can attribute an IP used by another computer on the network

[Stéphane Ascoët]

Package: isc-dhcp-client
Version: 4.1.1-P1-15+squeeze3
Severity: important

Powering on two computers and a DHCP at the same time, I find sometimes an IP-conflict between the two computers.

I think that this could happen:
The first computer uses another DHCP client than dhclient, it asks for an IP and gets 192.168.1.3 by the DHCP server.
The second computer uses dhclient, reading the leases file, it successfuly pings the router. So it keeps its 192.168.1.3 IP for example.

Why dhclient doesn't ping the computer IP(like it does with the router one) before keeping it without asking the DHCP server?

-- System Information:
Debian Release: 6.0.3
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: i386 (i686)

Kernel: Linux 2.6.32-5-686 (SMP w/1 CPU core)
Locale: LANG=fr_FR.UTF-8, LC_CTYPE=fr_FR.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages isc-dhcp-client depends on:
ii  debianutils         3.4                  Miscellaneous utilities specific t
ii  iproute             20100519-3           networking and traffic control too
ii  isc-dhcp-common     4.1.1-P1-15+squeeze3 common files used by all the isc-d
ii  libc6               2.11.2-10            Embedded GNU C Library: Shared lib

isc-dhcp-client recommends no packages.

Versions of packages isc-dhcp-client suggests:
ii  avahi-autoipd          0.6.27-2+squeeze1 Avahi IPv4LL network address confi
pn  resolvconf             <none>            (no description available)

-- no debconf information