questions about (system) dhclient

[Willy Offermans]

Hello Robert, Rick and FreeBSD friends,

On Tue, Apr 01, 2014 at 08:48:21AM -0400, Rick Miller wrote:
> On Mon, Mar 31, 2014 at 4:31 PM, Robert Huff <roberthuff at rcn.com> wrote:
> 
> >         [Please keep me CC'd as I am not subscribed.  Thanks.]
> >
> >         I have a system, running r263263, where dhclient is misbehaving.
> >  (Yes - this is CURRENT, but I have no reason to believe this inherently a
> > version-specific issue.  I am also on current@, and nothing like this has
> > been reported.)
> >         The system has an Intel Pro/1000 ethernet card, "em0", connected
> > to a Arris CM820 cable modem.
> >         This is the relevant portion of dhclient.conf:
> >
> > http://users.rcn.com/dhclient.conf
> >
> >         Upon execution, I get this:
> >
> > http://users.rcn.com/roberthuff/dhcp_offer
> 
> 
> The conversation between a DHCP server and client consists of the initial
> DHCP DISCOVER request from the client broadcasted to the network to which a
> DHCP ACK is expected in reply from an available DHCP server.  Upon receipt
> of DHCP ACK, the client sends another DHCP DISCOVER to the server asking
> for configuration information necessary to initialize networking.  The
> server's response is a DHCP OFFER containing all the information requested
> by the client.
> 
> I illustrate this in a sequence diagram describing a PXE workflow for
> FreeBSD installation at
> http://hostileadmin.com/images/FreeBSD_PXE_Install_Workflow.gif.  The first
> four steps in the sequence is the workflow's first DHCP conversation.
> 
> This output suggests only half of the conversation was completed.  The
> client doesn't appear to have sent the second DHCP DISCOVER and thusly did
> not receive configuration information from the server.  Have you ran packet
> captures to determine whether or not the whole conversation is occurring?
> 
> -- 
> Take care
> Rick Miller
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Does em0 supports TSO? and do you have ipfw running at the same time?
run ifconfig em0 and look for TSO!
I had some issues with bge0 and TSO. I noticed that both, natd and, most
importantly for your problem, dhcpd were increasingly using CPU load 
when an error occurred by sending an e-mail above a particular size. I 
figured out via the help of freebsd friends that ipfw and TSO are not 
compatible. Disabling TSO4 on bge0 solved the issue with sendmail and 
the CPU load of natd and dhcpd. Maybe you are facing a similar problem.

-- 
Met vriendelijke groeten,
With kind regards,
Mit freundlichen Gruessen,
De jrus wah,

Wiel

*************************************
 W.K. Offermans
e-mail: Willy at Offermans.Rompen.nl

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