Dealing with brute force on RHEL

Box got slow and decided to vim /var/log/secure and saw a bunch of brute force methods trying to ssh with names starting from A-Z.

iptables was installed so I added the ip via:

iptables -I FORWARD -s [ip] -j DROP
iptables -I INPUT -s [ip] -j DROP

It seemed like it blocked his ip automatically. I did:

iptables -nvL|less

Which showed his IP being supposedly blocked:

Chain INPUT (policy ACCEPT 26G packets, 9985G bytes)
 pkts bytes target     prot opt in     out     source               destination         
   23  1400 DROP       all  --  *      *       [HIS_IP]         0.0.0.0/0           
  26G 9985G PORTSEN    all  --  *      *       0.0.0.0/0            0.0.0.0/0  

Is this it? Do I need to use any command to actually save it? like service iptables save? Or is this automatically saved?

As a preventative measure, I'm going to follow a guide and add:

iptables -I INPUT -i eth0 -p tcp -m tcp --dport 22 -m state --state NEW -m recent --set --name DEFAULT --rsource
iptables -I INPUT -i eth0 -p tcp -m tcp --dport 22 -m state --state NEW -m recent --update --seconds 180 --hitcount 4 --name DEFAULT --rsource -j DROP

Are these measures enough for the low to medium level attacks? Would appreciate any input.