请教一个关于apache的错误日志的问题

[nonozone]

最近查看服务器上的apache的错误日志，发现有这么一堆

[Wed Oct 24 21:08:44 2012] [error] [client 124.115.1.7] File does not exist: /var/www/detail
1846 [Wed Oct 24 21:18:23 2012] [error] [client 31.210.123.132] File does not exist: /var/www/robots.txt
1847 [Wed Oct 24 21:18:23 2012] [error] [client 31.210.123.132] File does not exist: /var/www/robots.txt
1848 [Wed Oct 24 21:18:23 2012] [error] [client 31.210.123.132] File does not exist: /var/www/robots.txt
1849 [Wed Oct 24 21:18:23 2012] [error] [client 31.210.123.132] File does not exist: /var/www/robots.txt
1850 [Wed Oct 24 21:18:23 2012] [error] [client 31.210.123.132] File does not exist: /var/www/robots.txt
1851 [Wed Oct 24 21:28:07 2012] [error] [client 31.210.123.132] File does not exist: /var/www/robots.txt
1852 [Wed Oct 24 21:31:59 2012] [error] [client 199.30.59.172] File does not exist: /var/www/robots.txt
1853 [Wed Oct 24 21:46:35 2012] [error] [client 31.210.123.132] File does not exist: /var/www/robots.txt
1854 [Wed Oct 24 21:46:36 2012] [error] [client 31.210.123.132] File does not exist: /var/www/products
1855 [Wed Oct 24 22:14:20 2012] [error] [client 31.210.123.132] File does not exist: /var/www/robots.txt
1856 [Wed Oct 24 22:14:21 2012] [error] [client 31.210.119.210] File does not exist: /var/www/robots.txt
1857 [Wed Oct 24 22:51:39 2012] [error] [client 180.76.5.183] File does not exist: /var/www/robots.txt
1858 [Wed Oct 24 23:11:08 2012] [error] [client 157.55.35.79] File does not exist: /var/www/robots.txt


首先，/var/www这里现在是没有任何网站的，但是这个地址可以访问，里面有个index.php我自己做测试的，网站并没有放在这个目录，但是错误日志出现这么多内容，这一半是怎么造成的呢？

[TONYHEAD]

在/var/www下建立一个robots.txt

搜索引擎会默认爬robots.txt，如果找不到，日志里面就会出现404错误。