I would like to block FTP and Telnet on my server.

What will be the commandto use in IPTABLES.

have raed the IPtables how-to's so far
Tried the following but still not working.

FOR Telnet,
1)iptables -A INPUT --dport 23 -j DROP
2)iptables -A INPUT -p tcp --destination-port telnet -j DROP

iptables -A INPUT -p FTP -i eth0 -j REJECT
iptables -I FORWARD 2 -p tcp --dport 21 -j DROP.

What will be the command to block and enable FTP and Telnet