Most modern stacks default to HTTP/2 wherever they can, which is great for performance but awkward when older tooling or specific test scenarios depend on HTTP/1.1 framing. serveHttp11Action keeps the proxy itself on HTTP/1.1 for the matched exchanges, leaving everything else free to negotiate up.
serveHttp11Action controls the client to proxy leg of the connection. When the global ServeH2 option is enabled, Fluxzy normally advertises HTTP/2 to clients that support it. This action overrides that decision for matched exchanges so only HTTP/1.1 is offered during ALPN.
Reach for it when:
Note that this action only affects the connection between client and proxy. To control the proxy to server leg, use forceHttp11Action or forceHttp2Action.
Useful for tooling or browsers that crash on HTTP/2 framing for a specific upstream. The rest of the capture keeps using HTTP/2.
rules:
- filter:
typeKind: HostFilter
pattern: legacy.example.com
actions:
- typeKind: ServeHttp11Action
Pin both legs of the connection to HTTP/1.1 so the captured pcap is straightforward to read in any tool.
rules:
- filter:
typeKind: HostFilter
pattern: api.internal.example.com
actions:
- typeKind: ServeHttp11Action
- typeKind: ForceHttp11Action
Force the downstream connection (client-to-proxy) to use HTTP/1.1. When the global ServeH2 option is enabled, this action overrides it for matched exchanges by only advertising HTTP/1.1 during ALPN negotiation with the client.
Evaluation scope defines the timing where this filter will be applied.
onAuthorityReceived This scope denotes the moment fluxzy is aware the destination authority. In a regular proxy connection, it will occur the moment where fluxzy parsed the CONNECT request.
serveHttp11Action
This action has no specific characteristic
The following examples apply this action to any exchanges
Force HTTP/1.1 serving for a specific host even when ServeH2 is globally enabled.
rules:
- filter:
typeKind: AnyFilter
actions:
- typeKind: ServeHttp11Action
View definition of ServeHttp11Action for .NET integration.
This action has no related action
It controls the ALPN values that Fluxzy advertises to the client. With this action active, only http/1.1 is offered, so the client cannot upgrade to HTTP/2 on the proxy connection.
No. This action is scoped to the client side leg. Use forceHttp11Action or forceHttp2Action for the upstream leg.
No. ALPN negotiation happens during the TLS handshake, and the client simply picks the version Fluxzy advertises.
HTTP/1.1 cannot multiplex requests, so high concurrency clients may see lower throughput. Scope the rule to the hosts that actually need it.