Common Prefetch Links

DNS prefetching preconnect

	<!-- DNS preconnect -->
  <meta http-equiv="x-dns-prefetch-control" content="on">
  <link rel="preconnect" href="//ajax.googleapis.com">
  <link rel="dns-prefetch" href="https://fonts.gstatic.com">
  <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin="anonymous">
  <link rel="dns-prefetch" href="https://use.fontawesome.com">
  <link rel="preconnect" href="https://use.fontawesome.com" crossorigin>
  <link rel="preconnect" href="//cdnjs.cloudflare.com">
  <link rel="preconnect" href="//www.googletagmanager.com">
  <link rel="preconnect" href="//www.google-analytics.com">
  <link rel="preconnect" href="//mc.yandex.ru">
  <link rel="preconnect" href="//cdn.bitrix24.ru">
  <link rel="preconnect" href="//bitrix.info">

<!-- Amazon S3 -->
<link rel="dns-prefetch" href="//s3.amazonaws.com">

<!-- Google CDN -->
<link rel="dns-prefetch" href="//ajax.googleapis.com">

<!-- Microsoft CDN -->
<link rel="dns-prefetch" href="//ajax.microsoft.com">
<link rel="dns-prefetch" href="//ajax.aspnetcdn.com">

<!-- CDN JS -->
<link rel="dns-prefetch" href="//cdnjs.cloudflare.com">

<!-- Bootstrap CDN -->
<link rel="dns-prefetch" href="//netdna.bootstrapcdn.com">

<!-- Google Tag Manager -->
<link rel="dns-prefetch" href="//www.googletagmanager.com">

<!-- Google Analytics -->
<link rel="dns-prefetch" href="//www.google-analytics.com">

<!-- Google Fonts -->
<link rel="dns-prefetch" href="//fonts.googleapis.com">

<!-- Facebook -->
<link rel="dns-prefetch" href="//connect.facebook.net">

<!-- Google+ -->
<link rel="dns-prefetch" href="//apis.google.com">

<!-- Linkedin -->
<link rel="dns-prefetch" href="//platform.linkedin.com">

<!-- Twitter -->
<link rel="dns-prefetch" href="//platform.twitter.com">

I'm adding it to my site here. but all except google font. Google font is automatically deleted when I add it. what could be the reason

web site

dns-prefetch = DNS and preconnect = DNS + TCP + TLS. I think preconnect should be good enough