Re: Any other way for non-static IPs?

From: Joachim Maeland (jm-news_at_profine.net)
Date: 10/25/04 

Date: Mon, 25 Oct 2004 15:57:56 +0200

On Mon, 25 Oct 2004 05:30:07 -0700, Iceman wrote:

>> You need to have a static IP _before_ the dhcp sever starts.
>> otherwise it won't be able to serve any IP.
>
> Why is it not possible to say:
> - OK, I have eth0. It needs an IP.
> - I have a network definition 192.168.0 (netmask 255.255.255.0).
> - I can assign from a region 192.168.0.10 - 192.168.0.100.
> - OK, let's set it's IP to 192.168.0.44, for example.
> - Now, this eth0 has an IP and it's a broadcast network adapter.
> - As a DHCP server, I need some broadcast adapter to work on and eth0
> is one of them.

You can... Create the scripts to asign static random IP addresses.
Create scripts to test if the IP address can be used on your network. Give
this IP address to your DHCP-server and start it...

> The problem I want to address is: why not define only the network (by
> netmask) and the range of addresses that machines can get. A DHCP server
> should respond to any ethernet (i.e. broadcast) adapter it finds (or the
> adapter you give by a command line option). If it sees that eth doesn't
> have an IP address, no matter. Since it belongs to some network, we can
> configure automatically it by knowing the netmask and the range of
> addresses we have. Is this possible? In theory yes, but I don't know if
> in practice and if it was implemeted in current DHCP implemtations.

This is a proposed solution to a problem... What are you trying to do...?
What's the problem?
 
> If not by DHCP, is it possible to be done by any other way? The
> requirement is: I define (or get a definition by an upper authority) of
> a network (network IP and netmask) and I start a DHCP or whatever. That
> computer has ethernet eth0 which is assigned the given network IP (but
> NOT host IP!), it automatically assigns one from the given range of IPs
> and starts a server there.

If running 2 NICs you can assign a static IP for one of them. If your
DHCP-server is running "on" this NIC, the other NIC, and other computers
can use this server to get it's IP address.

You'll have to tweak your init scripts first, but it will work.

AFAIK; no DHCP-server can serve and assign IP addresses without using a
working NIC. A working NIC needs an IP address.

Anyway: What are you trying to accomplish and why do you insist on
going in this direction? 

-- 
mvh/regards
Joachim Mæland
If everything seems under control, you're just not going fast enough.
-Mario Andretti

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