Two active leases for client bug?

Simon Hobson dhcp at
Fri Mar 24 08:40:03 UTC 2006

Darko Bezjak wrote:

>I have problem with one clients which has receive two ip address at the same
>time. How is possible to get client two ip address and have two active
>records in lease file.

Because the client asked for two addresses using two different client 
IDs. Because the client ids are different, the requests are from 
different clients as far as the server is concerned - the client ID 
is the PRIMARY database key, with the MAC address used instead if no 
client ID is supplied.

>lease {

>   uid "\001RAS \000\021/H\261\261\000\000\000\000\000\000";

>lease {

>   uid "\001\000\300I\265\011\314";

If you dig back through the archives, you'll see that this is an old 
issue - Microsoft systems leasing addresses for their RAS service 
just in case a client should ever actually connect to it (they 
normally ask to 10 (yes TEN) addresses for RAS).

You can fix it either by turning off RAS on systems which don't need 
it, or by putting something like this in the dhcpd.conf :

if { substring (client-id,1,4)="RAS "
   ignore booting ;

You'll have to check the exact syntax with the man pages as I'm going 
from memory here.

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