We have seen a huge increase in individual servers/IP’s attempting to flood a server or brute force a particular account. Here’s a great way to check the number of connections being made from each IP that is connected to your server:
netstat -an|awk '{print $5}'|cut -d ":" -f1|sort|uniq -c|sort -n
We will post an automated method to check for an excessive number of connections and then block the IP’s if they hit a certain threshold. However, that article won’t be ready for a few days.