Stange records in access.log apache 2

Question

Today I notice stange records in access file of my apache 2 webserver

::1 - - [25/Jan/2011:14:13:31 +0200] "OPTIONS * HTTP/1.0" 200 -

Does anyone know what these lines means ?

Answer 1

Yes, it's an OPTIONS request, which is a feature used by some HTTP clients to query the server:

The OPTIONS method represents a request for information about the communication options available on the request/response chain identified by the Request-URI. This method allows the client to determine the options and/or requirements associated with a resource, or the capabilities of a server, without implying a resource action or initiating a resource retrieval.

It's commonly used by load balancers, firewalls and proxies to check up on the status of the HTTP server, without actually requesting a resource.

The ::1 at the start is an IPv6 address.