DHCP suddenly not working

[Rick Stevens]

Brenden T. wrote:
> Rick Stevens wrote:
> 
>> David Mackintosh wrote:
>>
>>> On Thu, Jun 10, 2004 at 09:21:52AM -0700, Rick Stevens wrote:
>>>  
>>>
>>>> This was 7.2?  I can't recall...does that use pump or dhclient?  If 
>>>> it's
>>>> dhclient, have you tried running it manually to see what actually goes
>>>> on?  You might try the same thing if it uses pump (do a "man pump" to
>>>> find what debug options there are).
>>>
>>>
>>>
>>>
>>> Back in the day, I had a RedHat firewall on @Home's cable network.  I 
>>> believe
>>> the vintage was 7.x, but I can't remember for sure.
>>>
>>> For what it's worth, here are my notes from that time:
>>>
>>> ----
>>> @Home is getting anal about dhcp.
>>>
>>> RedHat's default pump thing doesn't work, use dhcpcd instead.
>>> In /sbin/ifup, change the /sbin/pump command to
>>>
>>>          /sbin/dhcpcd -dR -I cr42217-a eth1
>>>
>>> ...where cr42217-a is this week's name assigned to you by @Home
>>> (you may have to use Windows to figure out what that is).
>>>
>>> Note that occasionally something seems to get f***ed up and you have
>>> to drop firewall protections in order to get a lease.  This is annoying.
>>> ----
>>>
>>> ...I believe that the -R switch told it not to mess with one of your
>>> /etc/resolv.conf and/or your default router (most likely the former).
>>
>>
>>
>> Thanks for the info.
>>
>> As far as the firewall, remember that you must accept data from port 68
>> over both TCP and UDP:
>>
>>     -A INPUT --sport 68 -j ACCEPT
>>
>> The options you specified for dhcpce are nothing new.  "-d" means to log
>> debug messages to syslog, "-H" means to set the hostname to that which
>> the DHCP server tells you.  The odd one is "-I".  Normally dhcpcd
>> behaves as if you used "-I" followed by the NIC's MAC address (hardware
>> address).  Where did you get the "cr42217-a" bit from?
>>
> 
> Thanks all for the info.  The connection is now partially working, with 
> a little manual intervention at startup.  At least some of the problem 
> was probably caused when I experimented on it but forgot to take down 
> the firewall (oops!).
> 
> Right now I'm investigating why it works once then quits if I reboot.  
> Maybe dhcpcd is not be stopped correctly?  The RH 7.2 scripts do a "kill 
> `cat /var/run/dhcpcd-${DEVICE}.pid`" for some reason.  I substituted 
> "/sbin/dhcpcd -k", we'll see if it helps.

Or "/sbin/killall dhcpcd"

> Note now that the procedure to start it is: 1. Shutdown network 2. Swap 
> DSL modem connect to other nic 3. Run a test dhcp on that nic ("dhcpcd 
> -T") which will succeed with the new nic, 4. Swap cable back, 5. Start 
> network and dhcp will succeed on the original nic (where it was failing 
> before).  Wild...

That's weird.  Have you watched the log or run it in the foreground to
see what it's doing?  Is it possible that the module used to drive that
NIC is having issues negotiating a speed or flow control issue?  What
kind of cards are you using?
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- Rick Stevens, Senior Systems Engineer     rstevens at vitalstream.com -
- VitalStream, Inc.                       http://www.vitalstream.com -
-                                                                    -
-                Huked on foniks reely wurked for me!                -
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