Checking the Apache server-status page I noticed multiple lines like the following:
| 29-39 | – | 0/0/3162 | . | 32.26 | 8949 | 0 | 0.0 | 0.00 | 186.48 | 123.111.123.111 | mywebsite.co.uk | OPTIONS * HTTP/1.0 |
| 30-39 | – | 0/0/10 | . | 0.00 | 24324 | 0 | 0.0 | 0.00 | 0.04 | 123.111.123.111 | mywebsite.co.uk | OPTIONS * HTTP/1.0 |
The access_log for that website also showed:
123.111.123.111 – – [18/Nov/2009:09:28:44 +0000] “OPTIONS * HTTP/1.0” 200 – “-” “Apache/2.2.3 (Red Hat) (internal dummy connection)” 2468
123.111.123.111 – – [18/Nov/2009:09:35:37 +0000] “OPTIONS * HTTP/1.0” 200 – “-” “Apache/2.2.3 (Red Hat) (internal dummy connection)” 1924
Apparently these are Apache calling itself to keep child processes alive:
When the Apache HTTP Server manages its child processes, it needs a way
to wake up processes that are listening for new connections. To do
this, it sends a simple HTTP request back to itself.
