[Netconf-devel] Re: setting up a router

[Frank Küster]

martin f krafft <madduck at debian.org> wrote:

> If this discussion turns into a technical one, let's switch lists!

done; I'm not subscribed to netconf-devel.

> netconf, this is about netenv and Frank's interest and experience
> with switching network configurations. Relevant posts are here:
>
>   http://albatross.madduck.net/pipermail/debian-unizh/2005-August/000578.html
>   http://albatross.madduck.net/pipermail/debian-unizh/2005-August/000579.html
>
> also sprach Frank Küster <frank at debian.org> [2005.08.09.1134 +0200]:
>> The main problem I had is that with a built-in NIC, one has to
>> change settings in /etc/networking/interfaces, while with a PCMCIA
>> NIC, variables are used.  In fact the last approach seems to be
>> nearer to what other distros do, and it is what upstream netenv is
>> taylored for, but today more mobile computers probably have
>> a network card built in.
>
> Debian's PCMCIA is configured to use /etc/network/interfaces unless
> you actually change it.

Yes, but since the upstream method uses environment variables, sourcing
the chosen netenv site file in /etc/pcmcia/network.opts is actually
better:  You then can use upstream's mechanism to interactively enter a
new network setup, which doesn't work for network/interfaces, since I
didn't dare to write code for this.  

Unfortunately, ATM each user has to setup the sourcing himself; I have
written to the pcmcia-cs maintainer about this long ago, but it seems I
forgot to file a bug.

> Having a way to specify at boot time which network profile to use is
> certainly a nice possibility. Nevertheless, I would implement it
> with tests.
>
>   configure eth0 for the university network if
>     (a) uni was selected at boot (through whatever means)

netenv uses dialog to display a list of choices in an init script called
as rcS.d/S40netenv.  This is quite convenient; of course the exact
timing is not without problems (and in fact it currently relies on the
undocumented, but established feature that sorting goes not only after
numbers, but alphanumeric, and S40netenv<S40networking).

>         - or -
>     (b) the uni's router replies to ARP pings

Nice idea, but the upstream author of netenv didn't write it that way.
If with the new network and init system there is an easy way to achieve
that, i.e. combine automatic detection with the possibility to manually
select something, and this gets the canonical way for Debian, then I
would gladly abandon the netenv package.  But as it is, there is some
motivation to do it like netenv does, and upstream currently doesn't
have autodetection (while other network chooser packages have).

When I was young and inexperienced ;-), I chose netenv exactly because I
didn't completely understand the implications of the autodetection
methods, ARP pings vs. IP broadcast pings vs. whatever.  Therefore I
thought having complete manual control would suit me best.

Today I could probably do well with the autodetection, but it seems
there are more people like I was, at least I get bug reports and there
are some popcon reports.

Regards, Frank
-- 
Frank Küster
Inst. f. Biochemie der Univ. Zürich
Debian Developer