Quoting Hendrik Boom (hendrik@???):

> On Sat, Oct 13, 2018 at 11:52:34PM -0700, Rick Moen wrote:
> >
> > If you look in /etc/resolv.conf, you'll see one or more 'nameserver'
> > lines. Mine on my server is like this:
> >
> > $ cat /etc/resolv.conf
> > search linuxmafia.com deirdre.org unixmercenary.net
> > nameserver 127.0.0.1
> > nameserver 198.144.192.2
> > nameserver 198.144.192.4
> > #nameserver 198.144.195.186
> > $
> >
> > (If you are getting your IP address using DHCP, you are extremely likely
> > to be getting passed nameserver IP addresses with your IP address lease,
> > resulting in the DHCP client software overwriting /etc/resolv.conf with,
> > among other things, 'nameserver nnn.nnn.nnn.nnn' information.
>
> Is there any practical way of suppressing this overwriting?

Yes, absolutely. (Not a complaint, but there was recent discussion of
that matter on Dng.) Write-up here:
http://linuxmafia.com/faq/Network_Other/resolvconf.html (Note, in
particular, item #3, 'Tweaking Your DHCP Client's Operation without
Resolvconf.'

> Or is it essential for the usual coffee-shop mode? Is the
> coffee-shop's DNS service is how my http: requests are hijacked to give
> me an advertising and agree-to-not-show-nudity page without which they
> cut me off?

{sigh} This is where things _sometimes_ become a little complex.

Many coffee-shop (and hotel, and similar) wifi networks rely on
something called a 'captive portal' to direct and force users to visit
a specific Web page immediately and either prove entitlement/payment or
formally consent to terms of service or both. In the cases I have in
mind, the WAP sends a DHCP lease with nameserver IP information that it
requests the client overwrite to /etc/resolv.conf . The initial purpose
of that nameserver is to categorically resolve any FQDN to the portal
Web site IP, pending customer authentication.

If you are travelling with a laptop and, say, object to /etc/resolv.conf
being overwritten every time there's a DHCP lease and take steps to
prevent that happening (as detailed in my write-up), you would silently
fail to reach the hotel (etc.) sign-in Web site and wonder why you're
neither seeing it nor any other remote destination, until you figure it
out and say to yourself 'Oh, right, I need to use _their_ cursed and
peculiar nameserver for the first two minutes so I can enter my Marriott
Rewards number, then I can switch back to nameservers I prefer.'



> And whih causes my browser to cut me off if it's https:?

I'm guessing: A nosy company that with a gateway designed to deny
privacy?