[Captive-portals] signaling no captive portal

[Michael Richardson <[e-mail]>]

Warren Kumari <[e-mail]> wrote:
    >> 2. There isn't a clear way to signal that there is no captive portal
    >> in the network.  It has been suggested that we use a special URL -
    >> e.g., urn:ietf:params:capport:unrestricted. Alternatively, we could
    >> privilege the empty string, but that doesn't have as clear a signal of
    >> intent.

    > Oooh, I like the special URL idea -- initially the thought was a
    > combination of:

    > 1: Until this is ubiquitously deployed (ha!), devices will need to do
    > CP heuristics, and so will discover the lack of CP through that.
    > 2: If there is no CP, no-one is likely to include the option.
    > 3: Since the vast majority of networks don't use CPs, is this an undue
    > burden on them?

In the case where there *was* a captive portal on a network, and now there is
not, it might be useful to tell clients that life has changed.  The client
might prefer to stay on 3G or pick another network rather than try that
portal.

It might also be meaningful to signal no-captive portal to clients which
have previously connected, but will no longer be challenged (ever? until DHCP
lease timeout?).  For instance, if I whitelist your laptop MAC address in my
home.

--
Michael Richardson <[e-mail]>, Sandelman Software Works
 -= IPv6 IoT consulting =-