ipV6 failing first time, working everytime subsequently

Francis Daly francis at daoine.org
Fri Jan 7 08:14:42 UTC 2022

On Thu, Jan 06, 2022 at 09:19:44PM -0500, chakras wrote:

Hi there,

> Thanks for your response. I have verified from Network logs on the browser
> that POST request is sending the username and password in both cases.

Where in the data flow is the username/password validated, that might
generate the 401 response that you see?

Should it happen in part of the nginx config that you have not shown; or
should it happen in the proxy_pass'ed request that you do not see happen?

> So, I
> wasn't sure if additional headers need to be sent for switching to happen
> seamlessly. The issue is after that first failure there is no subsequent
> failure for entire session of the application.

In general, for a browser doing normal web browsing, 401 followed by
200 is normal and expected. In your specific case, it may not be; and
the fact that it only-and-reliably happens when the client uses IPv6 not
IPv4 does seem odd. I think you indicated that the only mentions of a
401 response in your nginx logs are when the client has connected from
an IPv6 address.

> I am still trying to debug what can cause this issue.

Good luck with it,

Francis Daly        francis at daoine.org

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