Two consecutive lease entries for same MAC address
Simon Hobson
dhcp1 at thehobsons.co.uk
Tue Sep 22 12:55:04 UTC 2009
andreas.moroder at sb-brixen.it wrote:
>in our lease file I found consecutive lease entries for the same MAC
>address with two different IP adresses. The first one has no
>instructions for the dns registration and one vendor-string. The
>second has the dns information and a completely different
>vendor-string.
>The machines are thin clients ( old PCs ) that start from a intel
>bootable bios and then load thinstation.
>
>Can anyone please tell me why dhcpd ( ancient V3.0rc4 ) give two
>different IP addresses even if the MAC is the same ?
It's a classic "dual boot" problem where one client does not provide
a UID (aka Client-ID) and another does. The standard *requires* that
the DHCP server use the supplied Client-ID as the primary key, and
the MAC address only if no Client-ID is supplied.
Thus the two clients ARE DIFFERNET devices as far as the DHCP server
is concerned, and so they get different addresses.
>lease 10.53.39.212 {
<...>
> hardware ethernet 00:d0:b7:40:9d:aa;
> set vendor-string = "PXEClient:Arch:00000:UNDI:002001";
>}
>lease 10.53.39.247 {
<...>
> hardware ethernet 00:d0:b7:40:9d:aa;
> uid "\001\000\320\267@\235\252";
> set vendor-string = "udhcp 0.9.9-pre";
> set ddns-fwd-name = "derma-vormerk.sb-brixen.it";
> set ddns-rev-name = "247.39.53.10.in-addr.arpa.";
> client-hostname "derma-vormerk";
<...>
>}
--
Simon Hobson
Visit http://www.magpiesnestpublishing.co.uk/ for books by acclaimed
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