IP Address Problems

[Michael J. Lynch]

dan wrote:
> And @ mike
> 
> On 09/01/06, Michael J. Lynch <mlynch at gcom.com> wrote:
> 
>>dan wrote:
>>What does your /etc/network/interfaces file look like.  Post it if
>>there isn't anything you consider a security risk.
> 
> 
> /etc/network/interfaces
> <quote>
> # This file describes the network interfaces available on your system
> # and how to activate them. For more information, see interfaces(5).
> 
> # The loopback network interface
> auto lo
> iface lo inet loopback
> 
> # This is a list of hotpluggable network interfaces.
> # They will be activated automatically by the hotplug subsystem.
> mapping hotplug
> 	script grep
> 	map eth0
> 
> </quote>
> 
> The one on my spoofed laptop is the same except it has the following appended:
> 
> <quote>
> iface eth0 inet dhcp
> 
> auto eth0
> </quote>
> 
>>I your system is trully configured to use DHCP assigned IP addresses,
>>then your ISP's DHCP server is what assigns the addresses.  If it is
>>not obeying it's own lease durations and assigning you a new IP address
>>each time you log on, the problem is on their end.  That being said,
>>the DHCP server *will* give you a differenct IP address if your MAC
>>address is different.  Since you said something about spoofing MAC
>>addresses, this may be the source of the problem.  Especially if you
>>are using a different MAC address each time.
> 
> 
> Well, I started spoofing at least two months before the call, but I
> used the MAC address of my registered PC (am only allowed one NIC) to
> my laptop, and I never had (or was told) of any trouble until know.
> And since the registered NIC has problems as well...?
> 

Yep...my ISP has the same restriction.  The interfaces file on both
machines *should* be identical.  an contain the following:

<qoute>
auto lo
iface lo inet loopback

mapping hotplug
	script grep
	map eth0

iface eth0 inet dhcp
</qoute>

On the machine (laptop) that you want to use the spoofed MAC address
use the following (fill in the AA:BB... with the desired MAC address).

<qoute>
auto lo
iface lo inet loopback

mapping hotplug
	script grep
	map eth0

iface eth0 inet dhcp
	hwaddress ether AA:BB:CC:DD:EE:FF
</qoute>


Give that a try and see if it doesn't fix up the problem.  BTW - Make
sure you *never* have both machines on the same subnet at the same time
or you'll have lots of problems.


-- 
Michael J. Lynch

What if the hokey pokey IS what it's all about -- author unknown