Howto open ports

[misa.fisa]

Hello everybody,
I need an access from world to my router for port 1234. I have wan connected directly to the Internet (public IP). I try this command "iptables -I INPUT -j ACCEPT -p tcp --dport 1234".
I open port 1234 but only from lan. From wan it is still closed. Can anybody help me? Please?
I use this firmware 1.9.2.7-10

and I try also this command

iptables -t nat -A PREROUTING -i vlan1 -p tcp --dport 3128 -j DNAT --to-desination $4:3128

[admin@wl500gP sbin]$ ./post-firewall
iptables v1.2.7a: Unknown arg `--to-desination'
Try `iptables -h' or 'iptables --help' for more information.
[admin@wl500gP sbin]$

[DemonGloom]

and I try also this command

iptables -t nat -A PREROUTING -i vlan1 -p tcp --dport 3128 -j DNAT --to-desination $4:3128

[admin@wl500gP sbin]$ ./post-firewall
iptables v1.2.7a: Unknown arg `--to-desination'
Try `iptables -h' or 'iptables --help' for more information.
[admin@wl500gP sbin]$

destination

[misa.fisa]

destination
I don´t follow you.... What do you mean by destination?
I am little lost.
Thanks
My public ip on WAN is for example 132.132.23.2 and internal IP on LAN is 192.168.1.1

[vectorm]

I don´t follow you.... What do you mean by destination?
I am little lost.
Thanks
My public ip on WAN is for example 132.132.23.2 and internal IP on LAN is 192.168.1.1
You missed a letter 't' in word 'destination'. That's wrong.