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Re: Strange redirection to Cloudflare server with Captcha?

From: bruce via curl-users <curl-users_at_cool.haxx.se>
Date: Tue, 18 May 2021 15:15:02 -0400

Hi.

What's the code/snippet for your testing? Assuming you're doing a
quick/dirty code test, and not just a curl example from the cmd line.


On Tue, May 18, 2021 at 2:16 PM Petr Pisar via curl-users
<curl-users_at_cool.haxx.se> wrote:
>
> V Mon, May 17, 2021 at 09:27:16PM +0200, Mac-Fly via curl-users napsal(a):
> > > You need to compare the whole output (as I showed).
> > > Especially debugging of the TLS version, HTTP version,
> > > and HTTP headers.
> > I am afraid I don't know what to look at exactly.
> >
> > But if you look at the snippets I posted: The IP is different already after
> > the first lines (and these are the first lines of the log in verbose mode).
>
> www.audacityteam.org has 6 different IP addresses. You can you use "--resolve
> www.audacityteam.org:443:172.67.74.133" option to enforce connecting to
> 172.67.74.133 IP address.
>
> > Then it does no change.
>
> I did not know that.
>
> > One IP points to Cloudfare (the windows one), the
> > other does points to audacity (the Linux one).
>
> No. Both belongs to Cloufare. I tried both of them and both of them behave the
> same way for me as in your Linux example. Including TLS and HTTP protocol version
> and HTTP headers.
>
> > So I _think_ that already at
> > that point something was different for an unknown reason. :-/
> >
> TLS library, SNI support, maybe other things which cannot be seen from the
> log. Or it could be IP addess of the client. (Cloudfare can respond differently
> to the same requests arrived from different IP address.)
>
> Just for your reference I have:
>
> $ curl -V
> curl 7.76.1 (x86_64-pc-linux-gnu) libcurl/7.76.1 GnuTLS/3.7.1 zlib/1.2.11 libidn2/2.3.0 nghttp2/1.41.0
> Release-Date: 2021-04-14
> Protocols: dict file ftp ftps http https imap imaps mqtt pop3 pop3s rtsp smtp smtps tftp
> Features: AsynchDNS HTTP2 HTTPS-proxy IDN IPv6 Largefile libz NTLM SSL TLS-SRP UnixSockets
>
> I'm also short of ideas.
>
> -- Petr
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Received on 2021-05-18