I have a new question about iptables.

I have a router/internet gateway that has several different networks connected to it. There is 192.168.1.0/24, 192.168.2.0/24 and 192.168.3.0/24. The 192.168.2.0/24 network has a branch router of 192.168.2.30 that is connected to a 192.168.10.0/24 network. I would like to block access of the 192.168.10.0 network to the 192.168.1.0 network. What type of iptables command would I use on my gateway/router to do this?

Something like this:

iptables -A INPUT -s 192.168.2.30 -i eth2 -p all -d 192.168.1.0/24 -j DROP