{"record":{"id":"4a0a601b319d4238","repo":"router-for-me/CLIProxyAPI","slug":"claude-oauth-tls-dial-upstream-w","errorCode":null,"errorMessage":"claude oauth tls: dial upstream: %w","messagePattern":"claude oauth tls: dial upstream: %w","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"internal/auth/claude/utls_transport.go","lineNumber":212,"sourceCode":"\troundTripper.transport = &http.Transport{\n\t\tForceAttemptHTTP2: false,\n\t\tDialTLSContext:    roundTripper.dialTLSContext,\n\t}\n\treturn roundTripper\n}\n\nfunc (t *utlsRoundTripper) dialTLSContext(ctx context.Context, network, addr string) (net.Conn, error) {\n\tvar (\n\t\tconn net.Conn\n\t\terr  error\n\t)\n\tif contextDialer, ok := t.dialer.(proxy.ContextDialer); ok {\n\t\tconn, err = contextDialer.DialContext(ctx, network, addr)\n\t} else {\n\t\tconn, err = t.dialer.Dial(network, addr)\n\t}\n\tif err != nil {\n\t\treturn nil, fmt.Errorf(\"claude oauth tls: dial upstream: %w\", err)\n\t}\n\n\thost, _, errSplit := net.SplitHostPort(addr)\n\tif errSplit != nil {\n\t\tif errClose := conn.Close(); errClose != nil {\n\t\t\tlog.Debugf(\"claude oauth tls: close failed connection: %v\", errClose)\n\t\t}\n\t\treturn nil, fmt.Errorf(\"claude oauth tls: split upstream address: %w\", errSplit)\n\t}\n\ttlsConn := tls.UClient(conn, newClaudeOAuthTLSConfig(host, t.sessionCache), tls.HelloCustom)\n\tif errPreset := tlsConn.ApplyPreset(claudeOAuthTLSClientHelloSpec()); errPreset != nil {\n\t\tif errClose := tlsConn.Close(); errClose != nil {\n\t\t\tlog.Debugf(\"claude oauth tls: close connection after preset failure: %v\", errClose)\n\t\t}\n\t\treturn nil, fmt.Errorf(\"claude oauth tls: apply ClientHello: %w\", errPreset)\n\t}\n\thandshakeCtx := ctx\n\tif handshakeTimeout, _ := ctx.Value(claudeRefreshHandshakeTimeoutContextKey{}).(time.Duration); handshakeTimeout > 0 {","sourceCodeStart":194,"sourceCodeEnd":230,"githubUrl":"https://github.com/router-for-me/CLIProxyAPI/blob/78f0c4079e3e6273d65d03b5549cffc898703264/internal/auth/claude/utls_transport.go#L194-L230","documentation":"The uTLS-based OAuth transport failed at the raw TCP/proxy dial stage, before any TLS bytes flowed. dialTLSContext first connects through the configured (possibly proxy-aware) dialer; a failure here means network-level connectivity to the OAuth host (or to the configured proxy) is broken. The wrap includes the dialer's own error (DNS, refused, timeout, proxy failure).","triggerScenarios":"The Claude OAuth HTTP client dialing api.anthropic.com/claude.ai through direct or proxy dialing when: DNS resolution fails, the network is down, a firewall drops egress, or HTTPS_PROXY/ALL_PROXY points at a dead/unreachable proxy.","commonSituations":"Corporate environments where egress requires a proxy but HTTPS_PROXY is unset (direct connections blocked); misconfigured proxy env vars (typo'd host, wrong port, proxy requiring auth); DNS failures in containers with broken resolv.conf; firewalls blocking the OAuth endpoints specifically.","solutions":["Check the wrapped error: DNS failure → fix resolv.conf/DNS; connection refused/timeout → verify egress path to the OAuth host.","Set or fix HTTPS_PROXY/HTTP_PROXY/NO_PROXY so the OAuth dialer uses the corporate proxy (and ensure the proxy allows CONNECT to the OAuth hosts).","Test raw reachability: `curl -v https://api.anthropic.com` (with and without -x $HTTPS_PROXY) from the same host/container.","In containers, verify DNS and egress with a simple Go or curl probe before running the login/refresh flow."],"exampleFix":"# before\nunset HTTPS_PROXY   # direct egress blocked by firewall\n\n# after\nexport HTTPS_PROXY=http://proxy.corp.example:3128\nexport NO_PROXY=localhost,127.0.0.1","handlingStrategy":"retry","validationCode":"conn, err := net.DialTimeout(\"tcp\", \"api.anthropic.com:443\", 5*time.Second)\nif err != nil { return fmt.Errorf(\"egress to OAuth host blocked: %w\", err) }\nconn.Close()","typeGuard":null,"tryCatchPattern":"resp, err := oauthClient.Do(req)\nif err != nil && strings.Contains(err.Error(), \"dial upstream\") {\n    if isTransientNetErr(err) { time.Sleep(time.Second); resp, err = oauthClient.Do(req) }\n    if err != nil { return fmt.Errorf(\"check DNS/proxy egress: %w\", err) }\n}","preventionTips":["Verify HTTPS_PROXY/NO_PROXY match your network's real egress path before login/refresh.","Add a startup egress probe to api.anthropic.com:443 in restricted environments."],"tags":["claude","oauth","network","tls","proxy","dns"],"backgroundTag":null,"analyzedSha":"78f0c4079e3e6273d65d03b5549cffc898703264","analyzedAt":"2026-08-15T12:26:37.444Z","schemaVersion":2},"datasetVersion":"2026-08-15T22:17:37.221Z"}