Re: How does the resolv.conf get created?

[Filip Miletic <filmil gmail com>]

Dan Williams wrote:
> Not really, because NetworkManager needs to be able to configure DNS on the 
> machine.  If you're using DHCP, the DNS server information comes from the DHCP 
> server, and NetworkManager must write that out to /etc/resolv.conf so the 
> machine can resolve hostnames.  If the machine uses static IP, NetworkManager 
> must still do the same thing.

IMHO not needed. If I run a nameserver on the local machine,
'nameserver 127.0.0.1' is the only thing I ever need, regardless of
whether I use DHCP or not. system-config-network has an option not to
touch resolv.conf per entry.

> 
> Versions for FC4 and what's in CVS HEAD have the ability to use the localhost as 
> a caching nameserver, 
Looks like something I'd want.

> Do you use special resolv.conf settings, or have additional settings that you 
> give to BIND when you run it locally?  What exactly do you use BIND for in your 
> situation?

I use a simple caching nameserver. I use this as I have a peculiar
setup: I've a wired network card on a laptop. I usually access three
different networks with it: home net, lab net and office net. At the
office I have a fixed IP address and _no_ DHCP server. In the lab and at
home I use DHCP. For the fixed IP setting, I would need to manually set
the DNS. Running bind on localhost, and asking the s-c-n not to touch
resolv.conf solves the problem with the nameservers.

On my machine, the NM would need to check whether DHCP is available when
cable is plugged in, and if not, try the fixed IP address.

There is an alternative setting, which is not possible to obtain using
s-c-n as it does not allow setting default gateway metrics:

1) use eth0 with DHCP
2) use eth0:1 for fixed IP
3) set default route for eth0 with metric 0
4) set default route for eth0:1 with metric 1

This way, eth0 overrides eth0:1 if available. If other network is
available, set it also with metric 0. If not available, eth0:1 default
gateway with metric 1 takes over. Using metrics is a rather elegant way
to achieve what I need. I have not yet tested whether NM supports this.

> Yes, it would.  Its something on the to-do list.  What areas would be best to 
> work on first?  General usage and behavior?

Well, I would like to know:

- how to install it (the build instructions on the home page kind of
don't suffice...)
- how to configure it
- whether it uses the network settings I made with
system-config-network
- what is the criterion to choose between networks and how it can be
customized
- what network settings I can customize and how
- which programs I should start to use it; how to use it from the
command line (i.e. non-X)

f