AW: different DHCP-ack option through DHCP-request and DHCP-inform from same host

[Mohr, Andreas]

Hi shane,
thanks for your quick response.

Until a real solution, our workaround is to catch DHCP-inform messages:

 if option dhcp-message-type = 8 {
        if ((substring(option host-name,0,2) = "pc") {
            option domain-name-servers 10.147.9.109,10.147.9.111;
        } else {
            option domain-name-servers 10.165.0.66,10.166.1.20;
        }
    }

Is there an alternative to block DHCP-inform messages?


-----Ursprüngliche Nachricht-----
Von: dhcp-users-bounce at isc.org [mailto:dhcp-users-bounce at isc.org] Im Auftrag von Shane Kerr
Gesendet: Dienstag, 18. Juli 2006 14:49
An: dhcp-users at isc.org
Betreff: Re: different DHCP-ack option through DHCP-request and DHCP-inform from same host


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Mohr, Andreas wrote:
> hi,
> we using isc dhcp 3.0.4 under solaris9
> and observe different DHCP-ack option through DHCP-request and
> DHCP-inform packets
> from same host.
>  
> our config:

<snip/>

> Why dont use dhcp-ack for dhcp-inform not the group host
> domain-name-servers option?

I think the answer lies in this value in the DHCPINFORM packet:

    Relay agent IP address: 10.165.1.1 (10.165.1.1)

If this value (giaddr) is set, then DHCPINFORM uses it to decide which
subnet to use. The DHCPREQUEST relies only on the client address to
select the subnet.

I think this is a bug, but it was coded specifically to behave in this
way, so maybe there is something I'm missing. I'll check this out and
we'll fix it if it is a bug.

- --
Shane
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