Web Hosting - WordPress Varnish Cache

By default, WordPress generates pages dynamically--every time a user visits your site, which requires more resources to query the database and build the page from scratch.

Varnish is an in-memory caching solution designed to drastically speed up page load times. It uses the server's memory to save a completed copy of your web pages. Instead of building the page from scratch for every visitor, the server simply hands them the fast, cached version.

  • Web Pages: Cached for 1 hour.

  • Static Assets (Images, CSS, etc.): Cached for 24 hours.

Managing the Cache Because Varnish holds pages for an hour, live visitors might not see your new edits right away.  We recommend installing the Proxy Cache Purge plugin to automatically clear the cache for a specific page the moment you update it.

CDN based caching is also available: Web Hosting - WordPress - Content Delivery Network (CDN) with W3 Total Cache

Step-by-Step Plugin Configuration

    1. Request a Varnish Cache:  Email Varnish setup requests to webhosting@doit.wisc.edu and incluide your domain name(s).

    2. Locate your Site IP Address: Log into your Plesk Site Dashboard. You will find your site's IP address located in the bottom-left corner of the page.

    3. Enter the IP in WordPress: Log into your WordPress Admin dashboard. Navigate to Proxy Cache > Settings, enter your IP address into the appropriate field, and save your changes.

    4. Test the Configuration: Go to Proxy Cache > Check Caching and click the Run Full Cache Test button. If the setup is correct, a green success message appears.

    5. Verify the Toolbar Link: Navigate to any page on your site. You should now see a Cache (Active) link in your WordPress Admin toolbar at the very top of the page. You can use this link to manually clear the cache whenever necessary.

When to Manually Clear the Cache While the plugin handles most updates automatically, it sometimes misses dynamic feed pages. For example, if you publish a new article, your main "Posts" or blog feed page might still display an older, cached version without the new post.

-- If this happens, you can navigate to the main feed page and click the Cache (Active) link in your top toolbar to manually refresh it.

Questions? webhosting@doit.wisc.edu 


Keywords:
varnish purge purging wordpress proxy plugin 
Doc ID:
159520
Owned by:
Joe V. in DoIT Web Hosting
Created:
2026-03-05
Updated:
2026-04-14
Sites:
DoIT Web Hosting