Apache httpd won't stop doing reverse DNS requests for clients' IPs

Solution 1:

It seems the standard Ubuntu 8.04 Apache httpd install comes with a LogFormat that starts with %h and that does a client IP's RDNS lookup. Why oh why?? Replacing it with %a (remote IP address, see custom log formats) reduces this problem by ca. 90%. Some remain...

Solution 2:

Have you verified HostnameLookups is not set in any other directive? Have you activated the module mod_authz_host?