Problem obtaining IP from a cisco router
Brad Stockdale
brad_lists at greenepa.net
Thu Feb 8 17:26:06 UTC 2007
Jeremy is correct. The dhcp-excluded prevents them from being
dynamically leased.
Unfortunately, I still cannot figure out the problem that I'm
having... I've ran into this about a half dozen times over the past
six years, and it usually is with linux boxes...
I guess I'll just use a temporary fix for now -- install another NIC.
Thanks,
Brad
At 10:39 AM 2/8/2007, you wrote:
>S.Shunmuga,
>The ip dhcp-excluded address just tells the router that these
>addresses are not part of the DHCP pool and cannot be
>offered. There is nothing that prevents them from being leased
>statically. If you look back at Brad's config, you will see that
>the workstation that works fine is receiving a 172,16.208.58
>address, which is also inside the excluded range.
>
>Hope this helps clarify the command.
>
>Sincerely,
>
>
>Jeremy Bessee
>A+, CCNA, CCAI
>Glendale Community College
>Glendale, AZ USA
>jeremy.bessee at gcmail.maricopa.edu
>
>shunmugakrishnan wrote:
>
> >Hello all,
> >In the configuration file, you have specified a line
> >"ip dhcp excluded-address 172.16.208.1
> >172.16.208.100". The addresses in this range are not
> >available for DHCP server to assign to the client.
> >You have hard coded this 172.16.208.15 address to
> >billing. But since this falls in the range of excluded
> >address the server is not assigning this address.
> >
> >If you want to exclude only those two address, try
> >giving it in seperate lines
> >ex:
> >ip dhcp excluded-address 172.16.208.1
> >ip dhcp excluded-address 172.16.208.100
> >
> >I dont know much about cisco routers, but I just went
> >through their documentation, and it reads
> >"ip dhcp excluded-address low-address [high-address]"
> >So I thought this might be the problem.
> >
> >Am I missing something? :)
> >
> >Thanks & Regards,
> >S.Shunmuga Krishnan
> >
> >--- Brad Stockdale <brad_lists at greenepa.net> 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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> >>
> >>
> >>
> >>
> >
> >
> >
> >
> >__________________________________________________________
> >Yahoo! India Answers: Share what you know. Learn something new
> >http://in.answers.yahoo.com/
> >
> >
> >
>
>
>
>
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