I'm reading this tutorial which says,
Your gateway certificate must have: An Extended Key Usage flag explicitly allowing the certificate to be used for authentication purposes. The serverAuth EKU having the OID 22.214.171.124.126.96.36.199.1 (often called TLS Web server authentication) will do that. If you are using OpenSSL to generate your certificates then include the option
However, I'm confused as to what
gateway certificate means? Are they referring to the CA, the server's private key, or the public key you send to the client?
The argument they want
--flag serverAuth is valid in both
I don't understand the difference between