Date: Wed, 4 Nov 2009 09:18:48 +0100 (CET) From: "JASSAL Aman" <aman.jassal@esigetel.fr> To: Ask =?iso-8859-1?Q?Bj=F8rn_Hansen?= <ask@develooper.com> Cc: freebsd-net@freebsd.org Subject: Re: DHCP client not getting IP address from Time Warner Message-ID: <63471.83.206.131.26.1257322728.squirrel@webmail.esigetel.fr>
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Hello Ask,
Sorry for getting back to you so late T_T...
I've never faced a MAC address problem before, so I must say I was quite
surprised when I saw your logs yesterday evening.
I'm not sure what the nature of the problem exactly is (I didn't have time
to reproduce it yesterday evening either >_<),
I would suggest that you create your own dhclient.conf file (->
/etc/dhclient.conf) and specify the options you want to send in the
DHCPDISCOVER message yourself. The dhclient program starts by reading what
is specified in this file. You could try sending :
send {
dhcp-client-identifier "your MAC address"
ip-address "whatever IP address is topologically correct and with the
defined range of address the server can allocate"
}
With this, you clearly specify the MAC and the IP address you are
requesting (it is the parameters in the options field). You can also
specify other parameters if you wish to.
When you forced it, the MAC address was the good one, so that is good sign.
In the last log you sent (dhcp-freebsd-2.txt), the server is sending back
DHCPNAK messages, which occur in only 2 cases : either the client is
requesting an address that is topologically incorrect, or the lease of the
requested address has expired. But this, to me, looks like the DHCP server
was slightly confused about what was going on :)
Just try power-cycling your Time Warner device, so that he doesn't have
any record of any address.
If you specify clearly the options in your dhcpdiscover message by setting
them in the dhclient.conf, there's no reason the DHCP server will reject
your message. Whenever I configure my connection settings manually, I just
type :
# dhclient iwn0
(My interface uses iwn driver), and that works perfectly... I don't even
have a dhclient.conf file !
Hopefully it (setting up dhclient.conf) helps.
Kind regards,
Aman Jassal
Le Mar 3 novembre 2009 18:15, Ask Bjørn Hansen a écrit :
>
> On Nov 3, 2009, at 8:21, JASSAL Aman wrote:
>
>
>> Hello,
>>
>>
>> The logs display something that I find very disturbing.
>> In the dhcpdump log, the DHCPDISCOVER message your interface sends an
>> erroneous MAC address, there is a "01:" that is added in front of the
>> actual MAC address of your interface. What is sent in the discover
>> message is "01:00:..." instead of "00:00:...".
>
> Hi Aman,
>
>
> Yeah - I should have pointed that out. I tried forcing it to be
> correct with
>
> interface "vr1" { send dhcp-client-identifier 00:00:24:c9:23:c1; }
>
>
> to no effect.
>
> http://dl.getdropbox.com/u/25895/dhcp/dhcp-freebsd-2.txt
>
>
>> Then what happens explains itself : the DHCP server will send a
>> DHCPOFFER
>> by using the requesting client's MAC address, but since the given MAC
>> address is wrong, he broadcasts it (which I don't think is the behaviour
>> that is expected in normal cases...).
>
> I thought the broadcasts were misguided responses to me, too, at first
> -- but looking further I think it's just broadcasting when it's giving
> (or not) IPs to other clients. I've no idea why it does that.
>%20
>
> I only included one, but in
> http://dl.getdropbox.com/u/25895/dhcp/dhcp-osx.txt
> you can see that on OS X I get the weird replies to ff:ff:ff:ff:ff:ff, too.
>
>
> I also noticed that OS X adds two extra options in the request:
>
>
> OPTION: 57 ( 2) Maximum DHCP message size 1500
> OPTION: 51 ( 4) IP address leasetime 7776000 (12w6d)
>
>
> Just to test how can I make dhclient add those, too?
>
>
>>%20I think this is also why the client doesn't emit a DHCPREQUEST
>> (which is
>> emitted by the client to confirm that it is choosing the proposed
>> settings from the server, and implicitly turning down any other offers
>> made by other servers).
>>
>> I'll look into it when I get back home (at work right now). If
>> possible : could you try to connect your Time Warner cable with another
>> interface ? Or the same one as the one you used under Mac OS X %28that way
>> we would see if we get the same behaviour, regardless of the network
>> interface chosen) ?
>>
>
> The Soekris box only has vr interfaces; the OS X NIC is in my laptop
> so unless I install FreeBSD on there I won't be able to test that. :-) I
> did actually try one of the other vr interfaces on the Soekris box with
> the same result (they work fine with isc-dhcp running on another FreeBSD
> box).
>
>
> - ask
>
>
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