TLS

How roxy speaks TLS to clients on a proxy listener. Setting up the CA is in managing the CA.

Leaf certificates

roxy creates a certificate for each host the first time a client connects to it, signed by its CA. Certificates are ECDSA P-256 and valid for seven days, or until the CA expires if that is sooner. roxy keeps up to tls.leaf_cache_size of them.

Client-facing TLS

• roxy picks the certificate by SNI, or by the CONNECT host if the client sends no SNI. An invalid SNI fails the handshake.
• Host names are compared in lower case without a trailing dot, so CONNECT Example.COM.:443 with SNI example.com is one host.
• roxy offers HTTP/2 (with http.enable_h2) and HTTP/1.1.
• TLS 1.2 and 1.3 are supported. Sessions are not resumed.
• The handshake must finish within limits.header_timeout.

ClientHello sniffing

After a CONNECT, roxy reads the first TLS message to confirm that the tunnel carries TLS and to find the SNI. A ClientHello that is malformed, over 16 KiB, or split across several TLS records is treated as not TLS, and the connection is closed.