please,help me my server is attacked

[preleaf]

how to way to avoid the attack by strange IPs .I used this command line :
root@host [~]# iptables -A INPUT -s 220.73.136.254 -j DROP
bash: iptables: command not found
Please help me thank you so much
- Executed actions:
/etc/apf/apf -d 220.73.136.254

- Log events from /var/log/secure:
Oct 11 21:05:06 host sshd[15983]: Did not receive identification string from
220.73.136.254
Oct 11 21:05:07 host sshd[15984]: Did not receive identification string from
220.73.136.254
Oct 11 21:05:09 host sshd[15985]: Did not receive identification string from
220.73.136.254
Oct 11 22:05:06 host sshd[19518]: Failed password for nobody from 220.73.136.254
port 55116 ssh2
Oct 11 22:05:07 host sshd[19520]: Illegal user patrick from 220.73.136.254
Oct 11 22:05:09 host sshd[19520]: Failed password for illegal user patrick from
220.73.136.254 port 55162 ssh2
Oct 11 22:05:11 host sshd[19523]: Illegal user patrick from 220.73.136.254
Oct 11 22:05:13 host sshd[19523]: Failed password for illegal user patrick from
220.73.136.254 port 55217 ssh2

[ThaMATRiX]

http://forums.cpanel.net/showthread.php?t=30374

checkout that post.