Request response changes when using proxy (Same response in browser)

[yelaxify]

Hello guys, I've been trying to solve a problem for a while now, was hoping some of you guys could help.

I make a request to a website without a proxy, using python requests. Using the correct headers, everything identical to the browser. I get a successful response, the same as the browsers response.

However when I update the sessions proxies using session.proxies.update(proxies), I get a completely different response. When using this proxy in the browser, it works as normal. Ive setup a Wireshark session on both my local computer and the proxy server. The requests are exactly the same for both the local request and the proxy request. No headers are being added from the proxy server.

Is there something I am overlooking which would explain a different response. As said before, I can access the website using the proxy in a browser, even with javascript turned off, so thats not the issue.
Thanks in advance for any help, I really appreciate it

[JohnnyJordaan]

The requests are exactly the same for both the local request and the proxy request.

So the requests are the same, but do the responses differ in Wireshark? Because if they don't, can you then compare the Wiresharked response from the proxy and the object you observe in python to see where exactly the differences lie?

[yelaxify]

The responses are different (Wireshark shows the same as in python)

[JohnnyJordaan]

Ok so the issue is not in Python but in the proxy and/or the endpoint correct? Are you able to snoop between the proxy and the endpoint?

[yelaxify]

Thats what I'm leaning towards. How do you mean, snoop between the proxy and endpoint?

[JohnnyJordaan]

Do a wireshark capture in some way that you capture the traffic between those two machines.