Sitemap Caching

The Sitemap plug-in's sitemaps are potentially risky targets for denial of service attacks, since they are dynamically generated. A continuous stream of requests to a sitemap will quickly result in an unmanageable load on the servers. It is therefore vitally important to place the sitemaps behind a cache server. Responses from the sitemap service include Cache-Control response headers containing s-maxage directives specifying how long the sitemaps are to be cached.

The default Cache-Control settings included in the headers are:

• Aggregated sitemap: public, s-maxage=86400

• Update sitemap: public, s-maxage=300

It is important to either ensure that your cache server is respecting these settings, or else set up similar caching rules manually using the cache server's administration interface.