diff --git a/README.md b/README.md
index cf066bf..7778f66 100644
--- a/README.md
+++ b/README.md
@@ -35,8 +35,25 @@ Then:
 
     python sslproxy.py
 
-Then you can open `https://localhost:8443` in the browser.
+Then you can add the REST source (note the `httpS`):
 
-To add the REST source:
+    winget source add -n wpr -a https://localhost:8443/api/ -t "Microsoft.Rest"
 
-    winget source add -n "winget-pkgs-restsource" -a https://localhost:8443/api/ -t "Microsoft.Rest"
\ No newline at end of file
+### Sniff Microsoft's implementation
+
+Look at the `msstore` source shown by `winget source list`. Typically, it is:
+
+    https://storeedgefd.dsx.mp.microsoft.com/v9.0
+
+Start `sslproxy` as a man-in-the-middle proxy for the above domain:
+
+    python sslproxy.py 8444 storeedgefd.dsx.mp.microsoft.com 443 
+
+Then you can add the proxied source via:
+
+    winget source add -n ms -a https://localhost:8444/v9.0 -t "Microsoft.Rest"
+
+(Note that we used the path `/v9.0` from above.)
+
+Now you can inspect the traffic in the output of `sslproxy` when you perform
+`winget` commands.
\ No newline at end of file
diff --git a/sslproxy.py b/sslproxy.py
index 41ed2a6..0c2cb23 100644
--- a/sslproxy.py
+++ b/sslproxy.py
@@ -1,33 +1,84 @@
-import socket, ssl
+"""
+Usage:
 
+    python sslproxy [local_port] [dest_host] [dest_port]
+
+The defaults are local_port=8443, dest_host=localhost, dest_port=8000.
+"""
+
+import socket, ssl, sys
+
+from functools import partial
 from threading import Thread
 
-def forward(source, destination):
-    string = b' '
-    while string:
-        string = source.recv(1024)
-        if string:
-            destination.sendall(string)
+if len(sys.argv) > 1:
+    local_port = int(sys.argv[1])
+else:
+    local_port = 8443
+
+if len(sys.argv) > 2:
+    dest_host = sys.argv[2]
+else:
+    dest_host = 'localhost'
+
+if len(sys.argv) > 3:
+    dest_port = int(sys.argv[3])
+else:
+    dest_port = 8000
+
+def forward(source, destination, prefix=''):
+    data = b' '
+    while data:
+        try:
+            data = source.recv(1024)
+        except ConnectionResetError:
+            break
+        if data:
+            decoded = data.decode('utf-8')
+            for line in decoded.split('\n'):
+                print(prefix + line)
+            decoded = decoded.replace(
+                f'\nHost: localhost:{local_port}',
+                f'\nHost:{dest_host}'
+            )
+            destination.sendall(decoded.encode('utf-8'))
         else:
             source.shutdown(socket.SHUT_RD)
             destination.shutdown(socket.SHUT_WR)
 
-context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
-context.load_cert_chain(certfile="conf/localhost.cert", keyfile="conf/localhost.key")
+local_context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH)
+local_context.load_cert_chain(
+    certfile="conf/localhost.cert", keyfile="conf/localhost.key"
+)
+
+if dest_port == 443:
+    dest_context = ssl.create_default_context()
+else:
+    dest_context = None
 
 bindsocket = socket.socket()
-bindsocket.bind(('', 8443))
+bindsocket.bind(('', local_port))
 bindsocket.listen(5)
+bindsocket.settimeout(.5)
 
-print("Forwarding https://localhost:8443 -> http://localhost:8000")
+print(f'Forwarding localhost:{local_port} -> {dest_host}:{dest_port}')
 
 while True:
     try:
-        newsocket, fromaddr = bindsocket.accept()
-        client_socket = context.wrap_socket(newsocket, server_side=True)
-        server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
-        server_socket.connect(('localhost', 8000))
-        Thread(target=forward, args=(client_socket, server_socket)).start()
-        Thread(target=forward, args=(server_socket, client_socket)).start()
+        try:
+            newsocket, fromaddr = bindsocket.accept()
+            client = local_context.wrap_socket(newsocket, server_side=True)
+            server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            server.connect((dest_host, dest_port))
+            if dest_context:
+                server = dest_context.wrap_socket(server, server_hostname=dest_host)
+            Thread(
+                target=partial(forward, prefix='-> '), args=(client, server)
+            ).start()
+            Thread(
+                target=partial(forward, prefix='<- '), args=(server, client)
+            ).start()
+        except socket.timeout:
+            pass
     except KeyboardInterrupt:
         break
\ No newline at end of file