统计访问频次最高的10个ip:
cat /var/log/httpd/access_log |awk '{print $1}'|sort|uniq -c|sort -nr|head -10
统计恶意ip（结果为403的请求）
cat /var/log/httpd/access_log|awk '{if($9=='403'){print $1}}'|sort|uniq|sort -nr
请求样本如下：
61.160.207.44 - - [17/Mar/2015:06:30:55 +0000] "CONNECT reg.163.com:443 HTTP/1.0" 403 1374 "-" "Mozilla/5.0"