I've happened accross a odd issue this morning and I'm not sure where to go from here.
We use a couple of site up time monitoring services (pingdom, siteuptime) that essentially ping our server to check that its 'up'. Over the weekend both of these tools reported fairly large periods of outages.
Having looked through the Apache Access log for the reported down times I can see the requests coming in from both of these services. There are no errors reported in the error log against these times so I can only assume that the request was served as per normal.
I have already checked with our server hosts and they confirm that they had no downtime.
Is there such a thing as a sent log that details the actual pages that Apache has served? Can you think of any other avenues that I can check to see where this problem may have come from?
[EDIT] Extract from access_log
18.104.22.168 - - [12/May/2012:17:31:00 +0100] "GET / HTTP/1.0" 200 12056 "-" "Pingdom.com_bot_version_1.4_(http://www.pingdom.com/)"