Best way to check if there is internet?

[Chris Angelico]

On Tue, 8 Feb 2022 at 08:30, Cameron Simpson <cs at cskk.id.au> wrote:
>
> On 08Feb2022 06:51, Chris Angelico <rosuav at gmail.com> wrote:
> >Some day, we'll have people on Mars. They won't have TCP connections -
> >at least, not unless servers start supporting connection timeouts
> >measured in minutes or hours - but it wouldn't surprise me if some
> >sort of caching proxy system is deployed.
>
> The TCP ESTABLISHED state has no timeouts at all (though intemediate
> stateful things can get bored).  The setup/teardown do though :-)

That's what I mean - not a lot of point trying to establish a TCP
socket if the other end will give up on you after a mere ninety
seconds. It's extremely convenient that an established connection
lasts forever until touched in some way (even across reconfigurations
of the network - which is how you can redo a server's network over
SSH), but first you have to get to that!

> But
> they can be proxied. Our previous satellite modem proxied TCP locally
> and ran a more-suitable-satellite protocol from the modem to the
> downstation, where it became TCP again and went on its way.

Yup. I'm not sure whether we'll proxy TCP, proxy HTTP, or have high
level mirrors, but one way or another, people on Mars will want their
internets plsthx.

ChrisA