how to use the iptable firewall to restrict ssh,telnet,ftp

For SSH
iptables -A INPUT -s -p tcp --dport <22> -j
REJECT/DROP/DENY

For Telnet
iptables -A INPUT -s -p tcp --dport <23> -j
REJECT/DROP/DENY

For FTP
iptables -A INPUT -s -p tcp --dport <21> -j
REJECT/DROP/DENY