Reg Dnatting

Hi everybody,

I am using Redhat 9.0

Assume my public IP : 61.11.54.13

What ever requests come to the 5905 port on this ip should go to Http port on the private ip(192.168.30.233).

For this I Did destanation natting like this:
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -t nat -A PREROUTING -p tcp -d 61.11.45.13 --dport 5905 -j DNAT --to 192.168.30.233:80

But it is not working.(http://61.11.54.13:5905).

Is this enough or I need to configure anything.
And is DNAT require any changing of kernel parameters.

Please help me where I am doing mistake.

Thanks Inadvance.
Mummaneni