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upStreamProxyAction Action

Forward selected traffic through a parent HTTP proxy, with optional authorization, while keeping the rest of the session direct.

Proxy chaining is unavoidable in many enterprise environments. Routing some exchanges through a parent proxy while keeping the rest direct lets you debug applications inside the corporate perimeter without splitting your tool chain across two sessions.

When to use this action

Use upStreamProxyAction when Fluxzy itself must route certain exchanges through another HTTP proxy: a corporate gateway, a regional egress proxy, a privacy oriented intermediate, or a third party security solution. The action takes effect on the onAuthorityReceived scope, so you can target it by host or port even before any application data is exchanged.

Three common patterns:

  • Route internal traffic through a corporate proxy and let the rest go direct.
  • Send all traffic to a specific geography through a regional proxy to test geolocation logic.
  • Chain through an authenticating proxy by passing a pre encoded Basic auth header.

The proxyAuthorizationHeader is sent verbatim, including the scheme. For Basic auth, encode user:password in base64 and prefix with Basic. Other schemes such as Bearer also work as long as the upstream proxy accepts them.

Real world examples

Forward internal traffic through a corporate proxy

Match a corporate domain and route it through the company gateway. Other hosts continue to use the direct path.

rules:
- filter:
    typeKind: HostFilter
    pattern: '.*\.corp\.example\.com'
    operation: Regex
  actions:
  - typeKind: UpStreamProxyAction
    host: proxy.corp.example.com
    port: 3128

Use an authenticating proxy with Basic credentials

Pre encode the credentials in base64 to feed the proxy authorization header. Avoid hard coding secrets, prefer an environment variable injection in CI.

rules:
- filter:
    typeKind: AnyFilter
  actions:
  - typeKind: UpStreamProxyAction
    host: 192.168.1.9
    port: 8080
    proxyAuthorizationHeader: Basic bGVlbG9vOm11bHRpcGFzcw==

Combine an upstream proxy with skipSslTunnelingAction

Forward TLS traffic through the proxy without decrypting it locally, useful when the corporate proxy enforces its own inspection.

rules:
- filter:
    typeKind: HostFilter
    pattern: api.partner.example.com
  actions:
  - typeKind: SkipSslTunnelingAction
  - typeKind: UpStreamProxyAction
    host: egress.example.com
    port: 8080

Reference

upStreamProxyAction

Description

Use an upstream proxy.

Evaluation scope

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.

YAML configuration name

upStreamProxyAction

Settings

The following table describes the customizable properties available for this action:

Property Type Description DefaultValue
host string
port int32 0
proxyAuthorizationHeader string

Example of usage

The following examples apply this action to any exchanges

Use an upstream proxy to 192.168.1.9 on port 8080.

rules:
- filter:
    typeKind: AnyFilter
  actions:
  - typeKind: UpStreamProxyAction
    host: 192.168.1.9
    port: 8080

Use an upstream proxy to 192.168.1.9 on port 8080 with basic auth login: leeloo , password: multipass.

rules:
- filter:
    typeKind: AnyFilter
  actions:
  - typeKind: UpStreamProxyAction
    host: 192.168.1.9
    port: 8080
    proxyAuthorizationHeader: Basic bGVlbG9vOm11bHRpcGFzcw==

.NET reference

View definition of UpStreamProxyAction for .NET integration.

See also

This action has no related action

Frequently asked questions

Does Fluxzy still decrypt traffic when an upstream proxy is configured?

Yes, by default Fluxzy still acts as a man in the middle locally. Combine with skipSslTunnelingAction if you want the TLS to be end to end through the upstream proxy.

Which authentication schemes does proxyAuthorizationHeader support?

Whatever the upstream proxy accepts. Pass the full header value, including the scheme. Basic and Bearer are the most common, but NTLM single token responses are not handled because they need a challenge dance.

What happens if the upstream proxy is unreachable?

The exchange fails with a connection error, which appears in the Fluxzy timeline. Scope the rule tightly so unrelated traffic is not affected if the proxy is down.

Can I chain multiple upstream proxies?

Not natively. Fluxzy supports one upstream hop per exchange. If you need a longer chain, configure intermediate proxies independently.

Learn more about Fluxzy rules