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0xa

CONNECT_ERROR

Stream-levelRFC 9113 §7

CONNECT_ERROR (0xa) is sent when the TCP connection established for an HTTP CONNECT tunnel fails or is reset. HTTP/2 supports the CONNECT method (RFC 9113 §8.5) for tunneling TCP through an HTTP/2 connection. When the backend TCP connection for a CONNECT tunnel fails, CONNECT_ERROR is sent on the stream.

Code

0xa

Decimal

10

Standard

RFC 9113 §7

Description

The HTTP/2 CONNECT method extends the HTTP/1.1 CONNECT mechanism for creating TCP tunnels through a proxy. When a client sends a CONNECT request and the proxy establishes a TCP connection to the target, any TCP error on that proxied connection is reported back as CONNECT_ERROR on the HTTP/2 stream. The stream is closed with this code; the connection remains open for other streams. This is primarily relevant for HTTP/2 proxies implementing CONNECT tunneling.

Common Causes

  • –TCP connection to CONNECT tunnel target failed
  • –CONNECT tunnel target TCP connection reset
  • –Proxy backend connection refused
  • –Network error on the proxied TCP connection
RFC 9113 §7 – HTTP/2 Error Codes specification →