trusted connections
 

I am going to user iptables in my SuSE 9 in order to secure my system as much as i can.

One machine is going to get connected with my machine.

For example 192.168.1.4 it's the source

then my iptables should be

# iptables -A INPUT -s 192.168.1.4 -p tcp -j ACCEPT
# iptables -A INPUT -s ! 192.168.1.4 -p tcp -j DROP

Are the above commands correct?

I want none can touch my server except 192.168.1.4

Any ideas?

Those commands will accept any tcp connections originating from 192.168.1.4
Connections originating from another IP-address would be dropped.

This would protect your local computer from incoming connections. If this is a router/multihomed computer you will have to make other rules as well.