Hi there..

My porblem goes as such:

I live in a university flat where I connect to the network via dhcp.
The accomondation services allow only one nic to be
registered(pricks)..Anyway...

I have a box running slackware 10.0 (2.4.29) with a realtek gigabit
ethernet.. and a powerbook g4 with a sungem 10/100. I had the realtek's
mac-adress registered and connected via dhcpcd automatically, i could
connect the powerbook, running gentoo, by changing the mac-adress and
running dhcpcd which worked fine. The only problem I was facing was
that in MacOsX, in order to change the ethernets mac adress and get it
to work with dhcp the kernel had to be patched and I didn't have the
time nor the mood to fiddle with the darwin kernel at the time. So I
registered the p.books' adress and went happily to fire up dhcpcd in my
slack box...
Dhcpcd refuses to connect.. it hangs for a minute and then exits.

I run dhcpcd -d and get the following in the log entry:

Apr 5 23:02:01 mounaki dhcpcd[1660]: broadcasting DHCP_DISCOVER
Apr 5 23:03:01 mounaki dhcpcd[1660]: timed out waiting for a valid
DHCP server response

I've tried work arounds with the various options of dhcpcd but none
seems to give me the desired effect... every time it exits with the
above msgs at the end of the logfile...

Any thoughts on why i can't get a server response, suggestions ?

Regards
Chris.

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In alt.os.linux.slackware, mpekas@gmail.com dared to utter,
> I live in a university flat where I connect to the network via dhcp.
> The accomondation services allow only one nic to be
> registered(pricks)..Anyway...

I'm assuming this isn't a wireless network, if so, some of what I say
below may be inaccurate. It's atypical for a wired network to require
registering macs, but much more common for wireless network to do so as
they for some reason think that increases their security.[0]

> I have a box running slackware 10.0 (2.4.29) with a realtek gigabit
> ethernet.. and a powerbook g4 with a sungem 10/100. I had the realtek's
> mac-adress registered and connected via dhcpcd automatically, i could
> connect the powerbook, running gentoo, by changing the mac-adress and
> running dhcpcd which worked fine. The only problem I was facing was
> that in MacOsX, in order to change the ethernets mac adress and get it
> to work with dhcp the kernel had to be patched and I didn't have the
> time nor the mood to fiddle with the darwin kernel at the time.

This is true for 10.2 and earlier and only partially true for 10.3.
With Panther, you can trivially change the MAC address for the wired
connection with ifconfig $(man ifconfig; /lladr). For some insane
reason though, you cannot so easily do it with the AirPort Extreme
card. One caveat, there are some related dhcp problems, so google
before doing this.

> So I
> registered the p.books' adress and went happily to fire up dhcpcd in my
> slack box...
> Dhcpcd refuses to connect.. it hangs for a minute and then exits.

Could they have de-registered your realtek's MAC?

> I run dhcpcd -d and get the following in the log entry:
>
> Apr 5 23:02:01 mounaki dhcpcd[1660]: broadcasting DHCP_DISCOVER
> Apr 5 23:03:01 mounaki dhcpcd[1660]: timed out waiting for a valid
> DHCP server response

<snip>

> Any thoughts on why i can't get a server response, suggestions ?

Yeah I'd be willing to bet they de-registered that MAC. What I would
do if I was in your shoes is put a second NIC in your Slack box,
register it, and setup your Slack box to do NAT routing for a LAN, then
just connect your powerbook to the LAN. It's non-trivial if you've
never done anything of the nature, but is the best way to handle all of
this and stick it to the man, so to speak.

[0] Which is total bunk. 802.11a/b/g encrypted networks still send
some information unencrytped, such as the SSID. Among that information
are the MAC addresses for all the machines on the network. Recording a
MAC address of a legitimate user and spoofing it on an attacker's
machine is trivial.

- --
It is better to hear the rebuke of the wise,
Than for a man to hear the song of fools.
Ecclesiastes 7:5
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"mpekas@gmail.com" <mpekas@gmail.com> wrote:
>Hi there..
>
>My porblem goes as such:
>
>I live in a university flat where I connect to the network via dhcp.
>The accomondation services allow only one nic to be
>registered(pricks)..Anyway...

Get yourself one of those little 4 or 8 port routers, and put
that on the network as the one an only registered MAC address.
Then you can connect multiple other hosts to the router.

The only ones that I've played with also have wireless. A
Linksys WRT54G wireless, using Satori firmware would handle that
very nicely and also give you 802.11g wireless. I'm sure that
others would work well too.

Likewise just about any old PC, from a 486 on up, can be
configured as a router very easily (the WRT54G is just a little
Linux box with a 200MHz MIPS cpu). Put in two NIC's and add one
of those inexpensive multiport switches to it, and you've got a
*very* sophisticated and yet inexpensive router.

--
Floyd L. Davidson <http://web.newsguy.com/floyd_davidson>
Ukpeagvik (Barrow, Alaska) floyd@barrow.com

Hey Alan, thank you for replying.

> I'm assuming this isn't a wireless network,

You assume right.

> This is true for 10.2 and earlier and only partially true for 10.3.
> With Panther, you can trivially change the MAC address for the wired
> connection with ifconfig $(man ifconfig; /lladr). For some insane
> reason though, you cannot so easily do it with the AirPort Extreme
> card. One caveat, there are some related dhcp problems, so google
> before doing this.

I have actually tried changing the mac adress in Panther, it does
change and ifconfig shows the altered mac-adress. but by some
unexplained and mal reason it remains the same(initial) in the Network
panel.. as a consequence(!!) it does not connect to the dhcp server,
and the port gets deactivated, so no go for panther...


> Could they have de-registered your realtek's MAC?

I must apologize for my first post wasn't that clear. To answer your
question first: Yes they de-registered my MAC adress, I asked them to,
in order to register my powerbooks'.

So I de-register my desktops mac and through ifconfig I change it to
the one I recently registered(powerbook)..
Before i de-registered the desktops mac-adress, I could connect my
powerbook ,running linux, to the dhcp server with a spoofed adress (The
adress of my desktops' nic). It worked fine. I do the same thing in
slackware and it doesn't work at all. So, my question is: "Why is this
shit not working ? Are there ways to fix it? Might there be a chance
that the realtek is a gigabit ethernet and the sungem is not?"

(Please excuse me, again, for not being clear in the first place.)

> What I would do if I was in your shoes is put a second NIC in your
Slack box,
> register it, and setup your Slack box to do NAT routing for a LAN,
then
> just connect your powerbook to the LAN. It's non-trivial if you've
> never done anything of the nature, but is the best way to handle all
of
> this and stick it to the man, so to speak.

No £,Have to save up for a wireless dsl router and some wi-nics,
thanks for proposing. I would be gratefull if you could give me a hint
on the dhcpc matter tho.

Thank you for your patience..

Regards
Chris.

On Mon, 04 Apr 2005 21:40:27 -0700, mpekas@gmail.com wrote:


> ....
> So I de-register my desktops mac and through ifconfig I change it to
> the one I recently registered(powerbook)..
> Before i de-registered the desktops mac-adress, I could connect my
> powerbook ,running linux, to the dhcp server with a spoofed adress (The
> adress of my desktops' nic). It worked fine. I do the same thing in
> slackware and it doesn't work at all. So, my question is: "Why is this
> shit not working ? Are there ways to fix it? Might there be a chance
> that the realtek is a gigabit ethernet and the sungem is not?"
> ....

If I were you, I would have a look with tcpdump to see which MAC address
you are sending when you do the DHCP request. Maybe the ifconfig command
to change the MAC address isn't working on a realtek card.

John

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In alt.os.linux.slackware, mpekas@gmail.com dared to utter,
> Before i de-registered the desktops mac-adress, I could connect my
> powerbook ,running linux, to the dhcp server with a spoofed adress (The
> adress of my desktops' nic). It worked fine. I do the same thing in
> slackware and it doesn't work at all. So, my question is: "Why is this
> shit not working ?

That's a damn good question. I'm not sure we're going to be able to
answer it, because we don't have the information that the university's
dhcp server is getting. Perhaps if you could connect your powerbook up
to it via a hub and set your powerbook's network card to promiscious
mode, you could dump the dhcp traffic using something like snort. That
_might_ give us a clue as to what is going wrong, and please, let me
stress might.

> Might there be a chance
> that the realtek is a gigabit ethernet and the sungem is not?"

One being 10/100/1000 and the other being 10/100 shouldn't really make
a difference.

> No £,Have to save up for a wireless dsl router and some wi-nics,
> thanks for proposing. I would be gratefull if you could give me a hint
> on the dhcpc matter tho.

Wish I could help you there, but I'm fresh out of ideas short of noting
something odd via dumping the packets as I mentioned above. If you're
not very familiar with network protocols and how these things work
though, it's non-trivial, so it may be a little more than you want to
try. I still recommend getting another NIC for the slack box and
setting it up as a NAT router for your powerbook. If nothing else,
doing so should teach you something about TCP/IP.

- --
It is better to hear the rebuke of the wise,
Than for a man to hear the song of fools.
Ecclesiastes 7:5
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