Multi IP assign for single MAC-Urgent

arun.sasi1 at arun.sasi1 at
Mon Mar 14 14:46:53 UTC 2011

Dear Brad,

I have implemented the below please check was this correct configuration
.... Some times this is not working....

subnet XXX.XXX.39.128 netmask {
        ddns-updates on;
class "ras-clients" {
        match if substring (option dhcp-client-identifier, 1, 4) =
ignore booting ;
        ddns-domainname "";
        server-name "xxxxembinf01";
        max-lease-time 86400;
        default-lease-time 86400;
        option routers XXX.XXX.39.254;
        option netbios-name-servers XXX.XXX.243.102;
        option domain-name-servers XXX.XXX.243.100 , XXX.XXX.243.69 ,;
        # server-name "xxxxembinf01";
        # ddns-domainname "";
        pool {
                ddns-updates on;
                ddns-domainname "";
                range dynamic-bootp XXX.XXX.39.130 XXX.XXX.39.153;
                range dynamic-bootp XXX.XXX.39.154 XXX.XXX.39.167;
                range dynamic-bootp XXX.XXX.39.168 XXX.XXX.39.174;
                range dynamic-bootp XXX.XXX.39.175 XXX.XXX.39.177;
                range dynamic-bootp XXX.XXX.39.178 XXX.XXX.39.187;
                range dynamic-bootp XXX.XXX.39.190 XXX.XXX.39.248;


-----Original Message-----
From: at
[ at] On Behalf
Of Simon Hobson
Sent: Wednesday, January 05, 2011 12:54 AM
To: Users of ISC DHCP
Subject: RE: Multi IP assign for single MAC-Urgent

Brad Bendily wrote:

>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?

man dhcp-eval

>Alternatively, is there a better way to block or deny these devices?
>I have tried statically assigning them addresses, but that doesn't
>The MAC is very strange and I'm pretty sure we don't have any
>devices on the network.

Try searching the logs for those devices, it will probably give you more

Simon Hobson

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