[ipv6-wg] Question about how I handle web sites in my IPv6 survey

Hi there,

I'm seeking some views on how I should report some web failures on my 
IPv6 survey page <https://www.mrp.net/ipv6_survey/>.

If a site has both A and AAAA records for a web site I will try to 
connect to the IPv6 address and see if there is a web site listening 
there. It will start at tcp port 80 and then follow any redirects until 
hopefully it finds a 200 response.

The cases where it gets to a 200 are fine as that's "success" but there 
are some failure modes that I can't really make my mind up on so having 
some feedback would be potentially useful.

In all these cases I see a site with A and AAAA records so I connect on 
port 80 of the IPv6 address(es).

1. If the connection fails should I just report that or should I do 
anything more? For example see if the site responds via IPv4.

2. If the connection succeeds (so I assume there should be a working 
IPv6 based web server) but after querying it with a HTTP/1.1 message 
sees the site resets the connection (or fails in some other manner).

3. The connection succeeds as does the query and I get a 301 redirect to 
a location that fails to connect (typically it's the https port but 
could be another domain name). Again is this enough or should it do 
something else?

The difference is in how they are reported on the main survey page. If 
there is a problem then the cell will be blue but if I stop at the error 
then some indication of the error will appear in the cell. If after the 
failure I check if IPv4 works then the cell will still be blue but the 
indication in the cell will be the IPv4 status (more often than not this 
is success and so the indicator is type of connection (HTTP, HTTPS, 
HSTS, H2, etc) with a link to the web page.

At the moment I'm not consistent and I probably should be :-) but what 
type of indication is more helpful?

Finally in some cases I'll get a HTTP status code such as 403, 429 or 
503 rather than 200 and these are reported with a background of either 
light green or light red depending on whether it occurred on an IPv6 or 
IPv4 connection. Should these be blue rather than a different green/red?

Thanks,
Mark.