dump:/home/bk# iptables -t nat -A PREROUTING -p tcp -m tcp --dport 35 -j DNAT --to-destination 127.0.0.1:21
dump:/home/bk# iptables -t nat -A PREROUTING -p tcp -m tcp --dport 35 -j REDIRECT --to-port 21
dump:/home/bk# telnet localhost 35
Trying 127.0.0.1...
telnet: Unable to connect to remote host: Connection refused