Problem obtaining IP from a cisco router
Jeremy Bessee
jeremy.bessee at gcmail.maricopa.edu
Thu Feb 8 18:48:08 UTC 2007
Brad,
I just ran through your configuration on a 2611XM, IOS version
12.2(15)T16, and it ran flawlessly. The only thing I am not able to
test is Linux. Our labs are purely Windows XP.
Sincerely,
Jeremy
Brad Stockdale wrote:
>Hello all,
>
> I've ran into an interesting situation which may or may not be
>related to dhclient. It could very possibly be a configuration issue
>on my end, but I cannot seem to figure out what exactly is going on...
>
> At my office I have a Cisco 2620 router acting as the network
>DHCP server. On said router, I have a mix of both static and dynamic
>IP allocations. The relevant configuration is below:
>
>no ip dhcp conflict logging
>ip dhcp excluded-address 172.16.208.1 172.16.208.100
>ip dhcp bootp ignore
>!
>ip dhcp pool 172.16.208.0/24
> import all
> network 172.16.208.0 255.255.255.0
> default-router 172.16.208.1
> dns-server 67.135.184.20 67.135.184.21
>!
>ip dhcp pool computer1
> host 172.16.208.58 255.255.255.0
> client-identifier 0100.0475.99fe.e7
>!
>ip dhcp pool billing
> host 172.16.208.15 255.255.255.0
> INSERT LINE HERE...
>!
>
>The machine that is causing me grief is "billing". No matter what I
>do, I cannot seem to get the router to recognize the
>client-identifier that I specify. I have tried the following configs
>to see if I could get anything to work...
>
> hardware-address 00d0.b7a9.26c2
> hardware-address 0100.d0b7.a926.c2
> client-name 00d0.b7a9.26c2
> client-name 0100.d0b7.a926.c2
> client-identifier 00d0.b7a9.26c2
> client-identifier 0100.d0b7.a926.c2
> client-name "billing"
>
>I forget any other ones...
>
>In the dhclient.conf file, I have tried specifying the
>dhcp-client-identifier option to all the various iterations above. I
>have also tried setting the host-name to the same values.
>
>Here's what I'm seeing on the router:
>
>9w0d: DHCPD: checking for expired leases.
>9w0d: DHCPD: DHCPREQUEST received from client 00d0.b7a9.26c2.
>9w0d: DHCPD: Sending DHCPACK to client 00d0.b7a9.26c2 (172.16.208.129).
>9w0d: DHCPD: child pool: 172.16.208.0 / 255.255.255.0 (172.16.208.0/24)
>9w0d: DHCPD: pool 172.16.208.0/24 has no parent.
>9w0d: DHCPD: child pool: 172.16.208.0 / 255.255.255.0 (172.16.208.0/24)
>9w0d: DHCPD: pool 172.16.208.0/24 has no parent.
>9w0d: DHCPD: child pool: 172.16.208.0 / 255.255.255.0 (172.16.208.0/24)
>9w0d: DHCPD: pool 172.16.208.0/24 has no parent.
>9w0d: DHCPD: creating ARP entry (172.16.208.129, 00d0.b7a9.26c2).
>9w0d: DHCPD: unicasting BOOTREPLY to client 00d0.b7a9.26c2 (172.16.208.129).
>
>So, it assigns it the address 172.16.208.129, instead of the hard
>coded 172.16.208.15.
>
>The client-identifiers will not match with what I have tried on the
>router as far as the client-identifier or client-name or
>hardware-address lines...
>
>I have contacted Cisco about it, because my gut instinct is that the
>problem is on the router, not the dhclient. After working on it for a
>couple weeks on and off with Cisco, they came to the conclusion that
>they didn't know what was going on and couldnt fix it.
>
>Oh, here's a sh ip dhcp bind
>
>Bindings from all pools not associated with VRF:
>IP address Client-ID/ Lease expiration Type
> Hardware address/
> User name
>172.16.208.3 0100.5004.d7c6.7c Infinite Manual
>172.16.208.4 0100.104b.2b27.ca Infinite Manual
>172.16.208.5 0100.0502.37e5.9f Infinite Manual
>172.16.208.6 0100.e081.2e69.6a Infinite Manual
>172.16.208.7 0100.0d60.11f4.89 Infinite Manual
>172.16.208.8 0010.5aaa.8c7c Infinite Manual
>172.16.208.9 0100.9027.3a4c.55 Infinite Manual
>172.16.208.10 0100.0502.8e16.10 Infinite Manual
>172.16.208.11 0100.6097.bbfe.e6 Infinite Manual
>172.16.208.12 0010.4b21.5e02 Infinite Manual
>172.16.208.13 0100.3018.a5ea.1a Infinite Manual
>172.16.208.14 0100.1485.1e82.85 Infinite Manual
>172.16.208.15 00d0.b7a9.26c2 Infinite Manual
>172.16.208.58 0100.0475.99fe.e7 Infinite Manual
>172.16.208.101 0050.04d7.c67c May 03 1993 12:26 PM Automatic
>172.16.208.102 0100.c0b6.01b5.a3 May 03 1993 05:13 PM Automatic
>172.16.208.129 00d0.b7a9.26c2 May 03 1993 08:06 PM Automatic
>
>As you can see above, some of the Client-ID's have the 01 prepended,
>and some do not... I cannot figure out why the router detects some of
>then like that and others not. I know a Client-Identifier is partly a
>microsoft invention, but even when I use the hardware-address
>command, I cannot get dhclient to get the assigned address...
>
>I was hoping that maybe someone out there has ran into this before
>and can point me towards a solution or work-around.
>
>
>Thanks in advance,
>Brad
>
>
>
>
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