We were trying to check the log files for a site of ours to make sure a rewrite rule was working. Due to lack of rotation, the log file was 3GB and would not open in textpad (understandably). What a I really needed was a win32 version of tail. Voila – tailforwin32.sourceforge.net. It’s a GUI to view the last few lines of a file. It changes as lines are added to the file so you can view error or server logs in real time. Great we can check if the rewrite rules are working now. But is the last entry in the log file always exactly one hour ago.

2006-09-18 13:47:04 GET /Default.aspx – – 84.92.72.226 HTTP/1.1 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.1;+SV1;+.NET+CLR+1.1.4322) – 200 8307

After some research on W3C Log file formats (microsoft article), it turns out that it is the UTC time that is logged, not the LocalTime of the server. And since we are currently using daylight saving time (from March to October), which is UTC+1, which means that the UTC time of an entry in the log file looks like it’s an hour behind (from March to October anyway).

Mystery solved

And yes we have rotated the log files now.