diff --git a/PYTHON/mock_server/README.md b/PYTHON/mock_server/README.md
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+# Simulate Connection Failure
+
+(it takes ≈ 1hr to get it working)
+
+Install: https://mitmproxy.org/ (install it the way they recommend for your OS, for Ubuntu specifically apt version is 4 main versions behind newest version)
+
+Run it using `mitmproxy` 
+
+Run your webbrowser using `127.0.0.1:8080`  as proxy 
+on chromium-based browser it should be enough to do:
+`google-chrome --proxy-server=127.0.0.1:8080` 
+
+
+Run `mitmweb` 
+
+open 127.0.0.1:808**1**
+
+Click `File` in upper left corner and then `Install Certificates`  
+
+You should get a list of Windows/Linux/macOS/Firefox with certificates and how to install them 
+
+Install certificates using those instructions
+
+**important!** Go to your browser certificate settings and ensure that:
+
+1. mitmproxy certificate is imported
+2. **it is set to trusted**
+
+Now all of your network communication should go through mitmproxy, you can verify it by going to 127.0.0.1:808**1** and seeing constant flow of requests 
+
+## What can we do with it?
+
+1. Install mitmproxy python library using pip
+
+`pip install mitmproxy` 
+
+2. Copy and paste this “hello world”:
+
+```
+from mitmproxy import http
+
+def request(flow: http.HTTPFlow) -> None:
+    # Only intercept traffic to example.com
+    if "example.com" in flow.request.host:
+        flow.response = http.Response.make(
+            502,  # Bad Gateway status code
+            b"Simulated connection failure",
+            {"Content-Type": "text/plain"}
+        )
+
+```
+
+3. Run it: `mitmdump -s mitm_world.py`
+4. Go to [example.com](http://example.com) 
+5. You should see “simulated connection failure” in plain text
\ No newline at end of file
diff --git a/PYTHON/mock_server/mock_server.py b/PYTHON/mock_server/mock_server.py
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+++ b/PYTHON/mock_server/mock_server.py
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+from mitmproxy import http
+
+def request(flow: http.HTTPFlow) -> None:
+    # Only intercept traffic to example.com
+    if "example.com" in flow.request.host:
+        flow.response = http.Response.make(
+            502,  # Bad Gateway status code
+            b"Simulated connection failure",
+            {"Content-Type": "text/plain"}
+        )
diff --git a/PYTHON/mock_server/requirements.txt b/PYTHON/mock_server/requirements.txt
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+++ b/PYTHON/mock_server/requirements.txt
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+flask
+flask-cors
+mitmproxy
diff --git a/PYTHON/mock_server/run.sh b/PYTHON/mock_server/run.sh
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+++ b/PYTHON/mock_server/run.sh
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+#!/bin/sh
+mitmdump -s mock_server.py