[K12OSN] dhcpd problems

[Eric Harrison]

Alan Hodson wrote:
> I should have called this post "How do I recover from a dhcpd failure?"
> and hope to build a step by step 'What to check for' wiki help file, or
> one called 'how to prevent dhcpd failure' - it's exasperating!
> 
> dhcpd was installed, but 'service dhcpd start' would yield 'failed' -
> after many attempts at tweaking the greatly changed dhpcd.config file, I
> decided to use yumex to remove 'dhcp' and 'dhcp-ltsp-config' and
> re-install them via yumex install. The service is now running, and
> 'chkconfig --level 2345 dhcpd on' took care of starting it, but the thin
> clients are still generating a 'no dhcp' error. Tried a cross over cable
> to eliminate possible switch malfunctions to no avail. I did not have a
> chance to look at the /var/log/messages, but if I did, what info would
> help me?
> 
> Thanks Petre for all you do to help the group.
> 
> cheers
> alan
> -=o=- 

Here is a quick run-down of how DHCP works in K12LTSP (verisons 5 and 6)


* You need the dhcpd and dhcp-ltsp-config packages installed (as you noted)

* The dhcp-ltsp-config package installs the config file as 
"/etc/dhcpd-k12ltsp.conf" and edits /etc/sysconfig/dhcpd to point to 
that file:

     DHCPDARGS=" -cf /etc/dhcpd-k12ltsp.conf"

* the default /etc/dhcpd-k12ltsp.conf file expects the default K12LTSP 
installation configuration:

    - two network cards in the server
    - eth0 on the server has the IP address of 192.168.0.254 and
      netmask of 255.255.255.0

  If you have changed from the defaults, you will need to edit this file 
to match your configuration. Let us know how you've deviated from the 
defaults and we should be able to double-check that your config file is 
correct.

That's about it.



NOTE: since you mention that you re-installed the dhcp-k12ltsp-conf 
package, your old config file was probably saved as 
/etc/dhcp-k12ltsp.conf.rpmsave

NOTE#2: This is what /var/log/messages looks like when your IP address 
on eth0 does not jive with the IP ranges listed in /etc/dhcpd-k12ltsp.conf

> Nov 15 23:05:04 server dhcpd: 
> Nov 15 23:05:04 server dhcpd: No subnet declaration for eth0 (10.10.100.7).
> Nov 15 23:05:04 server dhcpd: ** Ignoring requests on eth0.  If this is not what
> Nov 15 23:05:04 server dhcpd:    you want, please write a subnet declaration
> Nov 15 23:05:04 server dhcpd:    in your dhcpd.conf file for the network segment
> Nov 15 23:05:04 server dhcpd:    to which interface eth0 is attached. **
> Nov 15 23:05:04 server dhcpd: 
> Nov 15 23:05:04 server dhcpd: 
> Nov 15 23:05:04 server dhcpd: Not configured to listen on any interfaces!
> Nov 15 23:05:04 server dhcpd: 
> Nov 15 23:05:04 server dhcpd: If you did not get this software from ftp.isc.org, please
> Nov 15 23:05:04 server dhcpd: get the latest from ftp.isc.org and install that before
> Nov 15 23:05:04 server dhcpd: requesting help.
> Nov 15 23:05:04 server dhcpd: 
> Nov 15 23:05:04 server dhcpd: If you did get this software from ftp.isc.org and have not
> Nov 15 23:05:04 server dhcpd: yet read the README, please read it before requesting help.
> Nov 15 23:05:04 server dhcpd: If you intend to request help from the dhcp-server at isc.org
> Nov 15 23:05:04 server dhcpd: mailing list, please read the section on the README about
> Nov 15 23:05:04 server dhcpd: submitting bug reports and requests for help.
> Nov 15 23:05:04 server dhcpd: 
> Nov 15 23:05:04 server dhcpd: Please do not under any circumstances send requests for
> Nov 15 23:05:04 server dhcpd: help directly to the authors of this software - please
> Nov 15 23:05:04 server dhcpd: send them to the appropriate mailing list as described in
> Nov 15 23:05:04 server dhcpd: the README file.
> Nov 15 23:05:04 server dhcpd: 
> Nov 15 23:05:04 server dhcpd: exiting.
> Nov 15 23:05:04 server dhcpd: dhcpd startup failed




-Eric

> On Wed, 2006-11-15 at 14:09 -0600, Petre Scheie wrote:
>> Please elaborate: The dhcpd package is still installed, correct?  So, re-installation 
>> isn't really necessary, correct?  Can you start the dhcp daemon?  Do you see any errors 
>> in /var/log/messages?  Etc.
>>
>> Petre
>>
>> ahodson at elp.rr.com wrote:
>>> Greetings from west Texas
>>>
>>> Can anybody help me find a way to re-install the dhcpd service in a (RH
>>> 5.0.32V) K12ltsp server?
>>> I've tried everything I know to make the service active again (power
>>> failure result), and all is well but the 30 student thin-client lab...
>>> I've even contemplated a complete re-install, but there are wiser and
>>> more knowlegdable colleagues out there... HELP!
>>> Cheers
>>> Alan Hodson
>>> El Paso ISD, TX
>>> http://links.episd.org/
>>> -=o=-