sending options from wrong subnet in shared-network

[Sten Carlsen]

Suggestions:

I see nothing in the host declaration that tells it which subnet to get
the IP from?
allow / deny may be your friend.

I would likely use class/subclass here with suitable allow/deny.

On 05/12/13 14:50, Brian J. Murrell wrote:
> I have a shared network configuration that looks like this:
> 
> shared-network foo {
>     subnet 192.168.0.0 netmask 255.255.255.0 {
>          option routers             192.168.0.1;
>          option domain-name         "subdomain.example.com";
>          option domain-name-servers 192.168.0.4;
>          option subnet-mask         255.255.255.0;
>          default-lease-time         21600;
>          max-lease-time             43200;
>     }
>     subnet 10.14.80.0 netmask 255.255.248.0 {
>          option routers             10.14.80.1;
>          option domain-name         "subdomain.example.com";
>          option domain-name-servers 10.14.80.8, 10.14.80.9, 10.14.80.6;
>          option subnet-mask         255.255.248.0;
>          range dynamic-bootp        10.14.80.100 10.14.83.254;
>          default-lease-time         21600;
>          max-lease-time             43200;
>          next-server                10.14.80.6;
>     }
> }
> 
> The problem is that clients seem to be getting an address from one
> network and options from the other in their reply:
> 
> 08:19:07.216363 52:54:00:0f:ce:31 > 52:54:00:19:d9:08, ethertype IPv4 (0x0800), length 344: (tos 0x10, ttl 128, id 0, offset 0, flags [none], proto UDP (17), length 330)
>     10.14.80.6.bootps > 10.14.81.56.bootpc: BOOTP/DHCP, Reply, length 302, xid 0x19d908, Flags [none]
>           Your-IP 10.14.81.56
>           Server-IP 10.14.80.6
>           Client-Ethernet-Address 52:54:00:19:d9:08
>           file "/pxelinux.0"
>           Vendor-rfc1048 Extensions
>             Magic Cookie 0x63825363
>             DHCP-Message Option 53, length 1: ACK
>             Server-ID Option 54, length 4: 10.14.80.6
>             Lease-Time Option 51, length 4: 10
>             Subnet-Mask Option 1, length 4: 255.255.255.0
>             Default-Gateway Option 3, length 4: 192.168.0.1
>             Domain-Name-Server Option 6, length 4: 192.168.0.4
>             Hostname Option 12, length 11: "lotus-19vm8"
>             Domain-Name Option 15, length 13: "subdomain.example.com"
> 
> That particular client is defined later in the configuration file as:
> 
>     host lotus-19vm8 {
>         hardware ethernet 52:54:00:19:D9:08;
>         filename "/pxelinux.0";
>         next-server 10.14.80.6;
>         option host-name="lotus-19vm8";
>         ddns-updates on;
>         ddns-hostname "lotus-19vm8";
>         ddns-domainname "subdomain.example.com";
>     }
> 
> So why is the server sending the options from the wrong subnet
> declaration?  Certainly it would be more clear if both the address and
> options being offered were from the wrong subnet declaration but it
> seems odd that the server would be giving an address from one subnet
> declaration and options from the other.
I see options from the host statement supplied with the missing pieces
from the subnet.
Again what in this host statement indicates which subnet it belongs to?
> 
> Ultimately what I am trying to achieve here is assigning
> "fixed-address"es for the first subnet and dynamic addresses for the
> second subnet where I have host declarations for all of my hosts and the
> dynamic ones look like the above and the fixed ones look like:
> 
>     host lotus-6-mgmt {
>         hardware ethernet 00:e1:76:d6:12:06;
>         fixed-address 192.168.0.6;
>         option routers 10.14.80.1;
The fixed address is not in the same subnet as the router? How can it
reach the router?
>         filename "/pxelinux.0";
>         next-server 10.14.80.6;
>         option host-name="lotus-6-mgmt";
>         ddns-updates on;
>         ddns-hostname "lotus-6-mgmt";
>         ddns-domainname "subdomain.example.com";
>     }
> 
> Cheers,
> b.
> 
> 
> 
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> 

-- 
Best regards

Sten Carlsen

No improvements come from shouting:

       "MALE BOVINE MANURE!!!"