Reverse proxying

Configuring Ferron as a reverse proxy is straightforward - you just need to specify the backend server URL in proxy directive. To configure Ferron as a reverse proxy, you can use the configuration below:

// Example configuration with reverse proxy. Replace "example.com" with your domain name.
example.com {
    proxy "http://localhost:3000/" // Replace "http://localhost:3000" with the backend server URL
}

Example: Ferron multiplexing to several backend servers

In this example, the example.com and bar.example.com domains point to a server running Ferron.

Below are assumptions made for this example:

• https://example.com is “main site”, while https://example.com/agenda is hosting a calendar service.
• https://foo.example.com is passed to https://saas.foo.net
• https://bar.example.com is the front for an internal backend.

You can configure Ferron like this:

* {
    tls "/path/to/certificate.crt" "/path/to/private.key"
}

example.com {
    location "/agenda" {
        // It proxies /agenda/example to http://calender.example.net:5000/agenda/example
        proxy "http://calender.example.net:5000"
    }

    location "/" {
        // Catch-all path
        proxy "http://localhost:3000/"
    }
}

foo.example.com {
    proxy "https://saas.foo.net"
}

bar.example.com {
    proxy "http://backend.example.net:4000"
}

For http://calender.example.net:5000/agenda/example, you will probably have to either configure the calendar service to strip ‘agenda/’ or configure URL rewriting in Ferron.

Load balancing

Ferron supports load balancing by specifying multiple backend servers in the proxy directive. To configure Ferron as a load balancer, you can use the configuration below:

// Example configuration with load balancing. Replace "example.com" with your domain name.
example.com {
    proxy "http://localhost:3000/" // Replace "http://localhost:3000" with the backend server URL
    proxy "http://localhost:3001/" // Replace "http://localhost:3001" with the second backend server URL
}

Health checks

Ferron supports passive health checks; you can enable it using lb_health_check directive. To configure Ferron as a load balancer with passive health checking, you can use the configuration below:

// Example configuration with load balancing and passive health checking. Replace "example.com" with your domain name.
example.com {
    proxy "http://localhost:3000/" // Replace "http://localhost:3000" with the backend server URL
    proxy "http://localhost:3001/" // Replace "http://localhost:3001" with the second backend server URL
    lb_health_check
}

Caching reverse proxy

Ferron supports in-memory caching for speeding up websites. To enable in-memory caching for the reverse proxy, you can use this configuration:

// Example configuration with caching reverse proxy. Replace "example.com" with your domain name.
example.com {
    proxy "http://localhost:3000/" // Replace "http://localhost:3000" with the backend server URL
    cache
    // Optional: set Cache-Control header if you want to also cache responses from backend servers without the Cache-Control header
    header "Cache-Control" "max-age=3600"
}