TsgcHTTP3Client › Properties › ConnectTimeout
Maximum time in milliseconds the client waits for the QUIC connection to be established.
property ConnectTimeout: Integer read FConnectTimeout write FConnectTimeout;Integer
10000 (10 seconds)
ConnectTimeout bounds the time spent opening a connection, which covers the QUIC handshake, the TLS 1.3 exchange and the h3 ALPN negotiation. When the handshake does not complete in time the attempt is abandoned. The timeout is enforced on the connect attempt itself, so a server that is unreachable or does not answer fails after ConnectTimeout, 10 seconds by default, instead of after the transport default of about 30 seconds.
If you are upgrading, note that this value was previously ignored. A connect attempt against an unresponsive server always took about 30 seconds, whatever ConnectTimeout said, because the handshake was left to the TLS library and its own budget. Code that sets a shorter value now gets the behaviour it asks for, so connect attempts can fail sooner than they used to.
The same timeout bounds two other waits that depend on the peer SETTINGS frame: ExtendedConnect waiting to learn whether the server allows Extended CONNECT, and WebTransportConnect waiting for the CONNECT status.
Time spent waiting for a response body is governed by ReadTimeout instead.
oClient.ConnectTimeout := 5000;