Can't get IP by DHCP (Wired network)

[NoOp]

On 07/09/2007 02:36 PM, Dmitry Bond wrote:

> 
> 
> 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! :(
> 
> 
> 

>From a previous:
$ cat /etc/network/interfaces

iface eth0 inet dhcp
address 87.237.115.100
netmask 255.0.0.0
gateway 87.237.115.1

*I think* the netmask and gateway is wrong. I think it should be:

netmask 255.255.255.0
gateway 192.168.100.1

87.237.115.1 is the internet facing gateway, 192.168.100.1 is the
intranet/lan facing gateway. netmask 255.0.0.0 is for your entire ISP.

This may help (read the full 3 pages):
http://ubuntuforums.org/showthread.php?t=465423
The user there solved it by changing his netmask to 255.255.248.0 Why
that worked I haven't a clue, but it's worth taking a look at.

One note: if the modem is 192.168.100.1 and you are getting
192.168.100.11, the you *are* being issued a proper IP for the subnet
192.168.100.x. And you can ping from 192.168.100.11 to 192.168.100.1 and
access that IP via your web browser.

If all else, you can buy a cheap hub and try firestarter:

sudo apt-get install firestarter

Set it up for NAT, see:
http://www.fs-security.com/docs.php
 http://www.fs-security.com/docs/dhcp.php
  http://www.fs-security.com/docs/connection-sharing.php

Then it wouldn't matter what your cable provider says/thinks. However,
I'd recommend that you buy a inexpensive but well branded router w a
built in firewall & install that instead. Many will include features for
MAC spoofing & DHCP.

Info for your modem:
http://broadband.motorola.com/consumers/products/sb5101/