Can't get IP by DHCP (Wired network)

[Derek Broughton]

Dmitry Bond wrote:

> Yeah, I tried that. Same results. But I tried to use
> /etc/init.d/networking restart, because my system didn't recognise the
> word 'dbus'.

Drat!  I missed part of the command line.  You really can't just pick a
random command if the ones we tell you don't work.  "networking" doesn't do
anything like "dbus".

It should have been:

# sudo /etc/init.d/dbus restart

That takes down dbus, hal, and the NetworkManager daemon and restarts them. 
That should ensure that NM can now see the device that it clearly isn't
seeing in the first place.

> I have 1 external IP bought and a limit up to 3 internal IPs. When my
> ISP is giving me the IP (when I connect the desktop to the modem) it
> acts like that: "Hmm... Someone from MAC: xxxx (desktop mac)
> connected.... What do I have in my database??? Oh yeah, this man
> bougth an IP registered to this MAC. I'll give it to him... " and I
> get it. Maybe more complicated, but it's what is said by the admins on
> the local forums. And I've checked: my outer IP, but wrong MAC = no
> internet. Dunno how they do it, really... And for example, if I plug
> in a new device with MAC, that is unknown for my ISP, I should phone
> my ISP and register this MAC, and they enter it to some database.
> Otherwise, no internet  :(.

But that just determines the address that DHCP _gives_ you.  Ask any hacker,
IP spoofing is simple, and I guarantee that your ISP can't stop it.  At the
very worst, you just change your MAC address (yes, you can do that - but
not, I think, using NetworkManager).  What I'm suggesting is that just
because you set an IP address on your interface, and couldn't get a
connection, doesn't mean that your ISP blocked you - it almost certainly
means you didn't set up your routing  correctly.

> I see that I don't get anything. If I turn my modem OFF (In that mode
> it serves as DHCP server itself I bet), then it gives me something
> like 192.168.100.11 (the modem is 192.168.100.1). But I expect that
> the modem should be on and I get something like 87.237.115.* or
> anything else... I'm totally confused with that things! :(

Get yourself a cheap router.  Set its MAC address to the one your ISP knows
about, and have it serve up the DHCP.  Then you not only don't have to
fight over MAC addresses, but your ISP won't be able to enforce any "3
internal IP" restriction, either.
-- 
derek