ASP.NET Core unable to use Forwarded Headers

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5

Yep, so I needed the following ForwardedHeadersOptions:

builder.Services.Configure<ForwardedHeadersOptions>(options => 
{
    options.ForwardedForHeaderName = "Fly-Client-IP";
    options.ForwardedHeaders = ForwardedHeaders.XForwardedFor;
    options.KnownNetworks.Add(new IPNetwork(IPAddress.Any, 0)); // This needed to be added
    options.KnownNetworks.Add(new IPNetwork(IPAddress.IPv6Any, 0)); // This needed to be added
});

Yes given the app is behind your proxy I guess it’s ok to allow from any address. Some folks who are a little more security conscious than me may not want to do that.

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