links on pages that match the [[ikiwiki/PageSpec]] automatically use
the `cgiauthurl`, and prevents matching pages from being edited by
users authentication via other methods.
+
+## Using httpauth with nginx
+
+You have to pass the $remote_user variable to the CGI:
+
+ location /ikiwiki.cgi {
+ fastcgi_param REMOTE_USER $remote_user if_not_empty;
+ ....
+ }