NetworkManager: I want to believe, but...

[James Antill]

On Fri, 2008-05-23 at 15:40 +0200, Hans Ulrich Niedermann wrote:
> Matthew Miller wrote:
> 
> > But "is the network up" a generally useful question?
> 
> I can picture several situations where "this system is online" or "this 
> system is offline" can cause more harm than it solves problems.

 Can you think of any good ones?

> "Is *the* network up?" "No."
> 
>    Now software will refuse to connect to 127.0.0.1, ::1 or any
>    other locally configured network address, for that matter - even
>    though these addresses are local and can be reached locally without
>    any network being connected.
> 
>    cf. https://bugzilla.redhat.com/show_bug.cgi?id=443385
>        Firefox refuses to connect to http://127.0.0.1/ when "offline"

 firefox isn't required to do this, testing for "localhost" is not that
hard. You could argue the same about "blah.example.com" when it resolves
to 127.0.0.1 ... but latency of DNS lookups are the leading cause of
firefox being unresponsive for me, AFAICS.

> "Is address 1.2.3.4 or dead:beef::1 reachable?" "Yes/No."
> 
>    This would be a better question locally running software could
>    ask.
> 
>    The answer could be determined by just looking at the local routing
>    tables (aka "ip route" and "ip -6 route" output).

 I don't know about you but I rarely type IPs into anything, so the
normal question would be more likely is "blah.example.com" available?
And if the answer involves waiting for the DNS requests to timeout then
it's much worse.

 Also this takes a view of the internet staying with single
destinations ... for instance yum using tools really don't want to have
to test if every destination in all the repo. mirrors files are
"unavailable" if you aren't actually on a wireless network.

-- 
James Antill <james at fedoraproject.com>
Fedora