Fw: Undefine The Failover Protocol and DHCP Daemon can not Build successfully

[Lin Shu-ping]

On Thu, 4 May 2006 09:11:59 -0700, David W. Hankins wrote
> On Thu, May 04, 2006 at 11:49:41PM +0800, Shu-Ping Lin wrote:
> >     From time to time I can not get the IP from DHCP server. After 
sniffing 
> > the packet I found that the DISCOVER, OFFER and REQUEST phases function 
> > correctly, but finally the DHCP server will NAK the user's request. It 
> > happened seldom and I do not know how to reproduce this problem and 
where 
> > the problem is. So I just want to disable failover protocol to see if it 
> > will happen again after that.
> 
> Well, you can do that without recompiling the daemon...it's just a
> config change.
> 
> Ask on dhcp-users if you need help with that.
> 

  O.K. Thanks. I will figure out it.

> >     I have traced the code in dhcp.c, in particular the function 
> > dhcprequest(). However, I still get any thought about this problem.
> >     Does anyone have any idea or suggestion?
> 
> If the server NAKed the lease, it is either because something
> changed that caused the server to deny the client permission to use
> a given pool (do you use reject/allow statements?), or the server
> believed the lease was assigned to a different client.

  I didn't configure any deny or permission related settings in 
configuration file. The strange thing is that if the DHCP server has found 
lease during dhcp request and respond the OFFER to user, why does it NAK 
this user's REQUEST? The OFFER is sent by itself and the server should not 
NAK it, right(without any permission configuration)? Is there any 
possibility that the server will NAK the user's REQUEST after it sent the 
OFFER to this client?

> 
> There was a failover bug fixed in 3.0.3, for example, where 'stale'
> client identifiers would be left on leases.
> 
> -- 
> David W. Hankins		"If you don't do it right the first time,
> Software Engineer	you'll just have to do it again."
> Internet Systems Consortium, Inc.		-- Jack T. Hankins

  I have traced the code of dhcprequest() and find_lease() function and 
there's only two or three situations that server will NAK the user's REQUEST.
  For example, this request comes from different shared network or wrong 
subnet and I am sure that this is not the case I encounter. So I really 
don't know what happened.

  If I have any thought wrong, please feel free to let me know.
  Thanks.

Best Regards,
Harry