Customer is running a script to POST data via HTTPS to an external web server and is seeing a "malformed packet" error message.
Pcap shows the ProxySG returning 400 bad packet after the client hello packet
400 bad packet
In an explicit proxy deployment when the client wants to access a web server over HTTPS the client must make a CONNECT request to the proxy before it tries to set up the SSL connection. If this does not occur the proxy will reject the connection. A pcap on the client side or from the proxy will show if the client is sending the CONNECT request or not.
Changing the script so that it used explicit connections to the ProxySG resolved the issue