[asterisk-users] OT: Problems with Linksys IP Phone SPA 942

[Vahan Yerkanian]

On 2/25/10 6:50 AM, Tilghman Lesher wrote:

> DHCP is designed in such a way that you can legitimately have multiple DHCP
> servers on the same network.  The first DHCP server which replies and meets
> the DHCP client's requirements will be the server to which the client
> registers.  If the Linksys DHCP server is faster (or if you have several
> switches and it replies to some hosts faster), then those hosts will likely
> use the Linksys as their DHCP server.
>
> You could technically avoid this situation by provisioning some DHCP option
> that the Linksys does not and making all of your DHCP clients require that
> option, but that takes quite a bit away from the zeroconf usage of DHCP.
> Or you could set up a rule on your managed switch such that broadcasts to
> UDP port 67 only hit the switch port on which your intended DHCP server is
> located.

I've been successfully using the following to catch Linksys phones and 
provide DHCP services only to them for the past few years:

class "Linksys" {
         match if ( substring (hardware,1,3)  = 00:0e:08 ) or ( 
substring (option vendor-class-identifier, 0, 7) = "LINKSYS" );
}

         pool {
                 allow members of "Linksys";
                 deny dynamic bootp clients;

                 range 10.168.172.100 10.168.172.250;
         }

HTH,
Vahan