Option 82 or subnet: who wins?

[David McGaughey]

Greetings list!  And my apology if I've missed this somewhere in my
googling.  I've a situation where I have an option 82 definition for a port
on a switch and a separate subnet definition. If I plug my client into the
switch port which has the class definition for a subnet AND I plug my dhcp
server into the switch port next to my client - same vlan - then I get a
mixture of the leases from both subnet definitions.  It would be nice to get
one or the other, and not a mixture of both.  Here's the config file:

 

option domain-name "ci.lubbock.tx.us";

option domain-name-servers 10.2.1.254, 10.2.1.253, 10.2.1.7;

default-lease-time 259200;

max-lease-time 259200;

ddns-update-style none; ddns-updates off;

authoritative;

subnet 172.25.254.0 netmask 255.255.255.0 {

  option subnet-mask 255.255.255.0;

  option broadcast-address 172.25.254.255;

  option routers 172.25.254.1;

class "ms_rm116_sw2650_hp1.0.17"

{

 match if (

         option agent.remote-id = 0:1d:b3:1f:c2:80

     and

         option agent.circuit-id = 0:11

      );

}

pool {

 range 172.25.254.47 172.25.254.49;

 allow members of "ms_rm116_sw2650_hp1.0.17";

}

}

subnet 192.168.50.0 netmask 255.255.254.0 {

 pool {

   option broadcast-address 192.168.51.255;

   option routers 192.168.50.1;

   option subnet-mask 255.255.254.0;

   default-lease-time 14400;

   max-lease-time 14400;

   range 192.168.51.1 192.168.51.254;

  }

}

 

Here's what the client (ipconfig /all) got:

 

 

 Windows IP Configuration

 

        Host Name . . . . . . . . . . . . : WXPITIMAGE03c

        Primary Dns Suffix  . . . . . . . : 

        Node Type . . . . . . . . . . . . : Unknown

        IP Routing Enabled. . . . . . . . : No

        WINS Proxy Enabled. . . . . . . . : No

        DNS Suffix Search List. . . . . . : ci.lubbock.tx.us

 

Ethernet adapter Local Area Connection 2:

 

        Connection-specific DNS Suffix  . : ci.lubbock.tx.us

        Description . . . . . . . . . . . : VMware Accelerated AMD PCNet
Adapter

        Physical Address. . . . . . . . . : 00-50-56-0F-0F-12

        Dhcp Enabled. . . . . . . . . . . : Yes

        Autoconfiguration Enabled . . . . : Yes

        IP Address. . . . . . . . . . . . : 192.168.51.4

        Subnet Mask . . . . . . . . . . . : 255.255.255.0

        Default Gateway . . . . . . . . . : 172.25.254.1

        DHCP Server . . . . . . . . . . . : 192.168.50.2

        DNS Servers . . . . . . . . . . . : 10.2.1.254

                                            10.2.1.253

                                            10.2.1.7

        Lease Obtained. . . . . . . . . . : Friday, March 13, 2009 11:43:21
AM

        Lease Expires . . . . . . . . . . : Friday, March 13, 2009 3:43:21
PM

 

Note that the IP Address comes from the second subnet, which happens to be
that of the DHCP server, but the netmask and the router come from the FIRST
subnet definition.

 

Neither subnet is winning now.  Should one of them be the "winner" and
assign all its information to the client?

 

David McGaughey <http://mcgoy.plumbearcat.com/> 

Lubbock, Texas

mcgoy at plumbearcat.com

(806)438-7363

 

 

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