What is the meaning of _ENV["HTTP_X_VARNISH"] values I get using phpinfo()

Question

When I run echo phpinfo() in root of application(Magento). I get _ENV["HTTP_X_VARNISH"] 1321634895

This means varnish cache is installed on server but what does 1321634895 value means. Do we have some default value for the same.

Please help me to understand this.

Answer 1

HTTP_X_VARNISH is just an internal ID of Varnish used to reference requests. You can use it for debugging purposes as the documentation says.