by jfkconsulting on WordPress.org
Customized 404 page, error logging with analysis, automatic redirects and export functionality.

This plugin allows you to take full control over how your WordPress site handles 404 (Not Found) errors. Instead of the default theme’s 404 page, you can:
noindex Tag: Automatically add a noindex, follow meta tag to your 404 pages (custom or default) to prevent search engines from indexing them.