看的 negative_ttl 的参数。

It seems that squid proxy somehow remembers the 403 Forbidden response and remembers it even if you reload the page which is already accessible.

Steps to reproduce:

1. Put some restriction to .htaccess (like deny from all). Open in browser, connected via squid proxy, error 403 appears.
2. Remove the restriction from .htaccess.
3. Reload the page - the error 403 is still present!

Look at negative_ttl parameter.