Hi,

Have had many sort of attacks from China, Brazil, and eastern Europe.

I use IPTables to block some countries completely. I get a master list from: http://www.wizcrafts.net/chinese-iptables-blocklist.html for example...

Once I get their list I put it into a script file and run it on the server. Something like this:

Code
#!/bin/bash
# china blocklist
# generated from http://blacklists.linuxadmin.org

/sbin/iptables -A INPUT -p tcp -s 58.14.0.0/15 --dport 22 -j REJECT
/sbin/iptables -A INPUT -p tcp -s 58.16.0.0/13 --dport 22 -j REJECT
/sbin/iptables -A INPUT -p tcp -s 58.24.0.0/15 --dport 22 -j REJECT

A few other things is I move my default SSH port. This helps tremendously. On my server it is controlled in the file /etc/ssh/sshd_config

I changed or added this line. Except I used my secret numbers. These are not the actual numbers I used.
Code
Port 1234

You may also want to consider moving your FTP ports as well. You can also do port scans against your server to see what is obviously visible to a hacker. There are tools for that at Sourceforge.net