ipv 4 and 6

[Stormy Weather]

On 2026-07-29 16:08, Maxim Dounin wrote:
> Hello!
> 
> On Wed, Jul 29, 2026 at 11:40:39AM -0400, Paul wrote:
> 
>> nginx/1.18.0 (Ubuntu).   For decades we have never explicitly "listened" for
>> 1pv6, using only "listen 443 ssl;" on a couple of dozen websites.
>>
>> As of two days ago, W3C (world wide web consortium) html, css, etc
>> verification tools are no longer functional -- our websites "time out" "500
>> Can't connect to mysite.com:443 (Connection timed out)"
>>
>> W3C have nslookup showing ipv4 and ipv6 addresses.  There is nothing in our
>> firewalls "denying" them, there is nothing in the nginx logs.
>>
>> I'm reticent to just add trillions of ipv6 possibilities of abuse (we're
>> experiencing om/off ddos attacks from ai/automated/bots to the tune of
>> 56^6/day).
>>
>> Any thoughts?
> 
> So, your website names resolves to both IPv4 and IPv6 addresses,
> but you don't have any IPv6 listens, correct?

Maxim, many thanks.  This might, or not, be IPv6 related

Our names only resolve to IPv4 (static 70.52.195.238 for nearly thirty 
years.)  For example:

CLI curl https://ultramarine.ca is functional through nginx proxied to 
apache2

But 
<https://validator.w3.org/check?uri=https%3A%2F%2Fultramarine.ca&charset=%28detect+automatically%29&doctype=Inline&group=0> 


returns "500 Can't connect to ultramarine.ca:443 (Connection timed out)"

and if I do a curl ultramarine.ca:443 on that same exact url I get

<center><h1>400 Bad Request</h1></center>
<center>The plain HTTP request was sent to HTTPS port</center>
<hr><center>nginx</center>

So W3C are reporting "time out" and nginx is apparently sending "400"

There is nothing in the nginx access or error logs

Spaseeba ee dobrey vyecher

Paul

> 
> This looks like a configuration error to me, and the fact that W3C
> tools fail isn't surprising.  There are two obvious solutions:
> either add relevant IPv6 listen directives, or remove the IPv6
> addresses from the website names.