Multi IP assign for single MAC-Urgent
Brad Bendily
Brad.Bendily at LA.GOV
Tue Jan 4 15:39:57 UTC 2011
Following the example provided below, I have tried a similar solution to
block some devices from using up addresses in one of my pool ranges.
>From the lease file:
lease 10.120.11.159 {
starts 2 2011/01/04 15:27:01;
ends 2 2011/01/04 15:29:01;
tstp 2 2011/01/04 13:27:02;
tsfp 2 2011/01/04 13:27:02;
atsfp 2 2011/01/04 13:27:02;
cltt 2 2011/01/04 15:27:01;
binding state free;
hardware token-ring 52:41:43:3f:dd:01;
uid "\0003fdd01-RACad1b02d940";
client-hostname "3fdd01-RACad1b02d940";
}
lease 10.120.11.164 {
starts 2 2011/01/04 15:24:40;
ends 2 2011/01/04 15:29:40;
tstp 2 2011/01/04 15:32:10;
tsfp 2 2011/01/04 15:32:10;
atsfp 2 2011/01/04 15:32:10;
cltt 2 2011/01/04 15:24:40;
binding state active;
next binding state expired;
hardware token-ring 52:41:43:e3:bc:00;
uid "\000e3bc00-RACe2ab02d940";
client-hostname "e3bc00-RACe2ab02d940";
So, I used this syntax:
if substring (client-id,1,4) = "RAC " {
ignore booting;
}
but, it doesn't seem to have made any effect on the usage of addresses.
I read through the man pages, but I just don't really get it.
What does the "client-id,1,4" part mean, and does that need to be
changed to make this work for me?
Alternatively, is there a better way to block or deny these devices?
I have tried statically assigning them addresses, but that doesn't work.
The MAC is very strange and I'm pretty sure we don't have any "token-ring"
devices on the network.
I think it's something strange happening on one of the network layers, but
without access to the network equipment myself, it's hard to troubleshoot.
Just wondering if someone can give me enough info to point my network
people in the right direction, or just to block these devices altogether.
Thanks
Brad B.
> -----Original Message-----
> From: dhcp-users-bounces+brad.bendily=la.gov at lists.isc.org
> [mailto:dhcp-users-bounces+brad.bendily=la.gov at lists.isc.org]
> On Behalf Of Glenn Satchell
> Sent: Monday, January 03, 2011 7:41 AM
> To: Users of ISC DHCP
> Subject: Re: Multi IP assign for single MAC-Urgent
>
> Hi Arun
>
> Looks like the gremlins got into the example, note the
> placing of the '{' on the first line :)
>
> if substring (client-id,1,4) = "RAS " {
> ignore booting;
> }
>
> This goes in /etc/dhcpd.conf, probably somewhere before the
> first subnet declaration.
>
> regards,
> -glenn
>
> On 01/03/11 23:53, Rudy Zijlstra wrote:
> > Hi Arun,
> >
> > the documentation of ISC documents this very well.
> >
> > I would suggest by starting to read "man dhcpd.conf". You will find
> > referrals to other good pages in there as well
> >
> > Cheers,
> >
> >
> > Rudy
> >
> > On 01/03/2011 01:36 PM, arun.sasi1 at wipro.com wrote:
> >> Ho to implement below in my Ubuntu server.
> >>
> >> if { substring (client-id,1,4)="RAS "
> >> ignore booting ;
> >> }
> >>
> >>
> >> -----Original Message-----
> >> From: dhcp-users-bounces+arun.sasi1=wipro.com at lists.isc.org
> >> [mailto:dhcp-users-bounces+arun.sasi1=wipro.com at lists.isc.org] On
> >> Behalf Of Simon Hobson
> >> Sent: Monday, January 03, 2011 6:02 PM
> >> To: Users of ISC DHCP
> >> Subject: Re: Multi IP assign for single MAC-Urgent
> >> Importance: High
> >>
> >> arun.sasi1 at wipro.com wrote:
> >>
> >>> This is a multi IP assignment for single host with DHCP server.
> >>>
> >>> I have dhcp server running in Ubuntu platform. I have configured
> >>> DHCP with "range". There is no MAC binding or reserve concept.
> >>>
> >>> Here I can see in my Webmin and dhcpd.lease database
> multiple active
> >>> IP for single host.
> >>>
> >>> I compared the two active lease and found that client are
> populating
> >>> and registered with two different UID for single MAC.
> >>>
> >>> Please help me to resolve this issue.
> >> Did you try searching the archives at all - it's a common and well
> >> known problem.
> >>
> >>> Logs
> >>> lease 163.183.39.238 {
> >>> starts 3 2010/12/29 06:01:26;
> >>> ends 4 2010/12/30 06:01:26;
> >>> tstp 4 2010/12/30 06:01:26;
> >>> cltt 3 2010/12/29 06:01:26;
> >>> binding state active;
> >>> next binding state free;
> >>> hardware ethernet e0:cb:4e:24:8c:27; uid "\001\340\313N$\214'";
> >>> client-hostname "MHAMZEHNAZ-IR16";
> >>> ------------------------
> >>>
> >>> lease 163.183.39.247 {
> >>> starts 2 2010/12/28 04:32:34;
> >>> ends 5 2010/12/31 04:32:34;
> >>> tstp 5 2010/12/31 04:32:34;
> >>> cltt 2 2010/12/28 04:32:34;
> >>> binding state active;
> >>> next binding state free;
> >>> hardware ethernet e0:cb:4e:24:8c:27; uid "\001RAS
> >>> \340\313N$\214'\000\000\000\000\000\000";
> >>> client-hostname "MHAMZEHNAZ-IR16";
> >> The key bit here is the uid starting with ""\001RAS ",
> which suggests
> >> this is a Windows server with RAS (Remote Access Service) enabled.
> >> These servers will automatically obtain (IIRC) 10
> addresses just in
> >> case a client should ever connect to it. If you aren't using RAS,
> >> then the easiest thing to do is to ignore such requests like this :
> >>
> >> if { substring (client-id,1,4)="RAS "
> >> ignore booting ;
> >> }
> >>
> >> See also :
> >>
> https://lists.isc.org/mailman/htdig/dhcp-users/2006-March/000273.html
> >
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