Thousands of head requests to my app using curl

[Kate]

See example below.

I am getting thousands of these per day and want to stop them. They are throwing HEAD / HTTP/1/1  errors.

They come from different IP addresses. I'm stumped!!!!!

> 2012-08-01 14:25:52.668 / 405 51ms 0kb curl/7.18.2 (i386-redhat-linux-gnu) libcurl/7.18.2 NSS/3.12.2.0 zlib/1.2.3 libidn/0.6.14 libssh2/0.18 
> 
> 193.136.19.13 - - [01/Aug/2012:12:25:52 -0700] "HEAD / HTTP/1.1" 405 124 - "curl/7.18.2 (i386-redhat-linux-gnu) libcurl/7.18.2 NSS/3.12.2.0 zlib/1.2.3 libidn/0.6.14 libssh2/0.18" "aussieclouds.appspot.com" ms=51 cpu_ms=0 api_cpu_ms=0 cpm_usd=0.000045 instance=00c61b117c01c1a2dec223c75dcfeaab60fbd7