web83info

This plugin allows a user to login by specific referer.
<h3>Donation</h3>
If you like this plugin, your donations are greatly appreciated.
https://www.buymeacoffee.com/web83info

Login by Referer

This plugin allows a user to login by specific referer.

ilanco

Hide Referer for WordPress removes the referer (referrer) from all external links on your blog. It does this by converting all outgoing 
links on your blog using the unrefer.com service and effectively hides your site as origin of the referred link.
For example, Hide Referer for WordPress will convert an external link to wordpress.com, to <a href="http://unrefer.com/?http://wordpress.org" rel="nofollow ugc">http://unrefer.com/?http://wordpress.org</a>.

WordPress Hide Referer

Test

Hide your referer (referrer) on all external links with unrefer.com.

Login by Referer vs WordPress Hide Referer