HardHat/docs/DnsPrefetch.md

DNS Prefetch sets the X-DNS-Prefetch-Control

Attack

When you visit a URL, the browser prefetches dns for a given link. This is a performance improvement, but can expose your users privacy by having them visit sites, they have never visited.

The Header

The X-DNS-Prefetch-Control header tells browsers whether they should do DNS prefetching.

Code

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
{
    app.UseDnsPrefetch(allow: false);
}