IPTables Question

[CodeHeads]

Hello all,

I have a question on IPtables:

The following is for a LAN based IP address:
iptables -A FORWARD -p tcp -s 192.168.1.0/24 -i eth0 -j DROP
iptables -A FORWARD -p udp -s 192.168.1.0/24 -i eth0 -j DROP

Can this be used for WAN IP's??  Something like this:
iptables -A FORWARD -p tcp -s 68.68.68.68 -i eth0 -j DROP
iptables -A FORWARD -p udp -s 68.68.68.68 -i eth0 -j DROP

And also can wild cards be used?
iptables -A FORWARD -p tcp -s 68.* -i eth0 -j DROP
iptables -A FORWARD -p udp -s 68.* -i eth0 -j DROP

Thanks in advance,
~WILL~