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Re: Adding openresolv to base

On Wed, Mar 25, 2009 at 09:17:10PM +0000, Roy Marples wrote:
> Michael van Elst wrote:
> >> You have not demonstrated a standard tool to allow multiple interfaces  
> >> to manage this.
> > 
> > For each interface you write the data into a parameter file. m4
> > will merge all data and apply the selection logic. If you think
> > this is too complex for m4, chose a real language.
> resolvconf does this also.

Yes it does.

> I don't see an option to remove data and restore prior data on link down
> though. How do your m4 scripts cater for that? Does it cater for merging
> from different interfaces?

m4 is just a macro expansion. You don't remove or restore data but
you can have a template that contains defaults. If no parameters
are given it will expand to some default (or some other data source).

> If we eliminate the task of the user having to script the writing of
> resolv.conf AND supply configurable knobs to ensure a valid resolv.conf
> persists when interface X goes up and down

Then we will still have the user writing scripts to do all the other

> It was meant to show that you don't need to learn $language to do a get
> a PPP link up with persistent DNS across multpile links provided that
> reasonable default scripts are supplied.

The 'reasonable default scripts' can do the same without another tool.

> Lets take your PPP example still.
> Network parameters - IP address added to the interface, check

that's obvious.

> routes - dhcpcd-5 can handle adding default routes to PtP destinations,
> check

It probably can't unless you have one interface and one route. Same
as ISC dhclient without custom scripting.

> DNS servers - added to resolvconf, check.

> Web proxy and mail gateway settings - where are these obtained from the
> PPP link?

DHCP can deliver service information. I'm not aware of a PPP option
that does.

> The reason why my tools don't care about your web proxy and mail gateway
> is this - they are not part of the auto-configuration of the interface
> from the supplied data.

see RFC 2132 for details what can be supplied as part of the
auto-configuration of 'the interface'. Very few people use it
that way, because there isn't one accepted standard, one reason
why you have to be flexible.

The latest attempt at a standard way for this is zeroconf.

                                Michael van Elst
                                "A potential Snark may lurk in every tree."

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