Cisco DHCP issue with multi-o/s environment

Dan · Guest

Cisco 1841 with Adv. IP

I'm having some trouble getting cisco's dhcp to work well in a mixed
environment with windows and linux.
Here is the problem, (which I understand also exists with ISC's dhcp
aswell). I want to assign static addresses to several machines, some
of which dual boot windows and linux. In the cisco config I would put
something like this:

ip dhcp pool GUEST
network 10.0.10.0 255.255.255.0
domain-name guest.tld
dns-server 65.106.1.196 65.106.7.196
default-router 10.0.10.1

ip dhcp pool testpool
host 10.0.0.38
hardware-address 0019.bbd7.fed7
default-router 10.0.0.2
dns-server 10.0.0.50

Using the above config, the linux box gets it's correct IP as
expected. When I reboot into windows, I get thrown onto the guest ip
block. Apparently for windows hosts, you must use client-identifier
rather then hardware address. It's the same thing, but prefixed with
a 01 to represent ethernet.

ip dhcp pool testpool
host 10.0.0.38
hardware-address 0100.19bb.d7fe.d7
default-router 10.0.0.2
dns-server 10.0.0.50

Now the windows box can get an IP, but rebooting into linux throws you
into the guest pool.

I contacted cisco, who's response was to make two pools for every
host. one with hardware-address and the other with client-identifier,
and set the lease time to be extremely short. While that sounded
rediculous, I tried it anyway. The router won't allow you to specify
two bindings with the same ip... What is the proper way to do this??
Am I going to have to get a cheap linksys router, and let that handle
dhcp ?

Below is my current config:
ip dhcp pool testpool
origin file tftp://10.0.10.100/1841-dhcp.txt
default-router 10.0.0.2
dns-server 10.0.0.50

and the file 1841-dhcp.txt:
*time* Jul 07 2007 01:17 PM
*version* 2
!IP address Type Hardware address Lease expiration
10.0.0.39 /24 1 0019.bbd7.fed7 Infinate
10.0.0.39 /24 id 0100.19bb.d7fe.d7
*end*

And the console output when the cisco loads that file:
000194: *Jul 5 14:21:41.291 PCTime: DHCPD: reading bindings from
tftp://10.0.10.100/1841-dhcp.txt.
000195: *Jul 5 14:21:41.299 PCTime: DHCPD: read 217 / 1024 bytes.
000196: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line "*time*
Jul 07 2007 01:17 PM"
000197: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line
"*version* 2"
000198: *Jul 5 14:21:41.299 PCTime: DHCPD: route: Parsed version = 2
000199: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line "!IP
address Type Hardware address Lease expiration"
000200: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line
"10.0.0.39 /24 1 0019.bbd7.fed7 Infinate"
000201: *Jul 5 14:21:41.299 PCTime: DHCPD: creating binding for
10.0.0.39
000202: *Jul 5 14:21:41.299 PCTime: DHCPD: Adding binding to radix
tree (10.0.0.39)
000203: *Jul 5 14:21:41.299 PCTime: DHCPD: Adding binding to hash
tree
000204: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line
"10.0.0.39 /24 id 0100.19bb.d7fe.d7"
000205: *Jul 5 14:21:41.299 PCTime: DHCPD: binding for 10.0.0.39
already exists.
000206: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line "*end*"
000207: *Jul 5 14:21:41.303 PCTime: DHCPD: read static bindings from
tftp://10.0.10.100/1841-dhcp.txt.

Aaron Leonard · Guest

Dan,

The IOS DHCP server does indeed have limitations such as you describe.
(Can't have a single "host" binding that maps to both a "hardware-address"
and a client-id.)

It would be nice if we had an option to make the hardware-address override
the client-id.

Regards,

Aaron

---

~ Cisco 1841 with Adv. IP
~
~ I'm having some trouble getting cisco's dhcp to work well in a mixed
~ environment with windows and linux.
~ Here is the problem, (which I understand also exists with ISC's dhcp
~ aswell). I want to assign static addresses to several machines, some
~ of which dual boot windows and linux. In the cisco config I would put
~ something like this:
~
~ ip dhcp pool GUEST
~ network 10.0.10.0 255.255.255.0
~ domain-name guest.tld
~ dns-server 65.106.1.196 65.106.7.196
~ default-router 10.0.10.1
~
~ ip dhcp pool testpool
~ host 10.0.0.38
~ hardware-address 0019.bbd7.fed7
~ default-router 10.0.0.2
~ dns-server 10.0.0.50
~
~ Using the above config, the linux box gets it's correct IP as
~ expected. When I reboot into windows, I get thrown onto the guest ip
~ block. Apparently for windows hosts, you must use client-identifier
~ rather then hardware address. It's the same thing, but prefixed with
~ a 01 to represent ethernet.
~
~ ip dhcp pool testpool
~ host 10.0.0.38
~ hardware-address 0100.19bb.d7fe.d7
~ default-router 10.0.0.2
~ dns-server 10.0.0.50
~
~ Now the windows box can get an IP, but rebooting into linux throws you
~ into the guest pool.
~
~
~ I contacted cisco, who's response was to make two pools for every
~ host. one with hardware-address and the other with client-identifier,
~ and set the lease time to be extremely short. While that sounded
~ rediculous, I tried it anyway. The router won't allow you to specify
~ two bindings with the same ip... What is the proper way to do this??
~ Am I going to have to get a cheap linksys router, and let that handle
~ dhcp ?
~
~
~ Below is my current config:
~ ip dhcp pool testpool
~ origin file tftp://10.0.10.100/1841-dhcp.txt
~ default-router 10.0.0.2
~ dns-server 10.0.0.50
~
~
~ and the file 1841-dhcp.txt:
~ *time* Jul 07 2007 01:17 PM
~ *version* 2
~ !IP address Type Hardware address Lease expiration
~ 10.0.0.39 /24 1 0019.bbd7.fed7 Infinate
~ 10.0.0.39 /24 id 0100.19bb.d7fe.d7
~ *end*
~
~
~ And the console output when the cisco loads that file:
~ 000194: *Jul 5 14:21:41.291 PCTime: DHCPD: reading bindings from
~ tftp://10.0.10.100/1841-dhcp.txt.
~ 000195: *Jul 5 14:21:41.299 PCTime: DHCPD: read 217 / 1024 bytes.
~ 000196: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line "*time*
~ Jul 07 2007 01:17 PM"
~ 000197: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line
~ "*version* 2"
~ 000198: *Jul 5 14:21:41.299 PCTime: DHCPD: route: Parsed version = 2
~ 000199: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line "!IP
~ address Type Hardware address Lease expiration"
~ 000200: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line
~ "10.0.0.39 /24 1 0019.bbd7.fed7 Infinate"
~ 000201: *Jul 5 14:21:41.299 PCTime: DHCPD: creating binding for
~ 10.0.0.39
~ 000202: *Jul 5 14:21:41.299 PCTime: DHCPD: Adding binding to radix
~ tree (10.0.0.39)
~ 000203: *Jul 5 14:21:41.299 PCTime: DHCPD: Adding binding to hash
~ tree
~ 000204: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line
~ "10.0.0.39 /24 id 0100.19bb.d7fe.d7"
~ 000205: *Jul 5 14:21:41.299 PCTime: DHCPD: binding for 10.0.0.39
~ already exists.
~ 000206: *Jul 5 14:21:41.299 PCTime: DHCPD: parsing text line "*end*"
~ 000207: *Jul 5 14:21:41.303 PCTime: DHCPD: read static bindings from
~ tftp://10.0.10.100/1841-dhcp.txt.