Duplicated leases, same IP and same MAC

[Simon Hobson]

<arun.sasi1 at wipro.com> wrote:

>Could you check Windows machine with RAS (Remote 
>Access Service) enabled or notŠ if it is 
>enabled, disable it from DHCP server or stop the 
>service and renew the IP..

It's nothing at all to do with that. In that 
case, you can clearly see the client-id the 
Windows box sends which starts with "RAS ". That 
isn't present in these leases.

carlos jorge wrote :

>Today i was looking into the lease file and 
>found something that i think that should not 
>happen.
>In the lease file i found 2 leases with the same 
>IP and MAC, to one par IP MAC there should exist 
>just one lease right?
>
>
>lease 10.43.11.92 {
>   starts 2 2011/09/20 14:57:21;
>   ends 2 2011/09/20 22:57:21;
>   tstp 3 2011/09/21 02:57:21;
>   tsfp 2 2011/09/20 22:57:22;
>   cltt 2 2011/09/20 14:57:21;
>   binding state active;
>   next binding state expired;
>   hardware ethernet 00:40:ca:a4:3f:be;
>   set ddns-txt = "0097558cd8aa1f47ff41f956ea212c89b8";
>   set ddns-fwd-name = "00:40:ca:a4:3f:be.teste.t";
>   client-hostname "T5413";
>}
>
>
>lease 10.43.11.92 {
>   starts 2 2011/09/20 14:57:21;
>   ends 2 2011/09/20 22:57:21;
>   tstp 3 2011/09/21 02:57:21;
>   tsfp 3 2011/09/21 02:57:21;
>   atsfp 3 2011/09/21 02:57:21;
>   cltt 2 2011/09/20 14:57:21;
>   binding state active;
>   next binding state expired;
>   hardware ethernet 00:40:ca:a4:3f:be;
>   set ddns-txt = "0097558cd8aa1f47ff41f956ea212c89b8";
>   set ddns-fwd-name = "00:40:ca:a4:3f:be.teste.t";
>   client-hostname "T5413";
>}
>
>
>After some minutes the file only had one.
>
>i tested with omshell and i saw the error:
>can't open object: more than one object matches key
>
>Witch means that in memory structure in DHCPd there are more 2 leases
>
>The version that i m running is  3.1.3, is this 
>the normal behavior? or its a bug? it's 
>corrected in newer versions?

It's normal to have more than one lease for a 
client/IP. The leases file is a "log file" - all 
updates are done by appending a new entry on the 
end and so it's normal to have multiple entries - 
though I'm surprised to see them with exactly the 
same timestamp.

Periodically (once an hour by default, I believe 
to change it means altering the source and 
recompiling) the server will write a new lease 
file containing only the last lease status as 
held in memory to a new file and swap it with the 
old leases file. Thus once an hour, the file is 
cleaned up and initially will only contain one 
record for each lease/IP.
Note that the only time the lease file is read is 
at service startup. During startup, the server 
reads each lease record and builds an in-memory 
record of the last status. AT all other times, 
the lease file is only written as an on-disk 
backup.

-- 
Simon Hobson

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