IPTABLES FORWARDING PROBLEM

My topology is as follows:

inet----router 192.168.1.254-------wlan0 192.168.1.71 && eth0
192.168.70.121------ip camera 192.168.70.140:80

Note:

(1) eth0 and wlan0 are on a PC running Ubuntu.

(2) Port 5555 on the router is forwarded to 80 on 192.168.1.71

(2) in sysctl I have set sysctl net.ipv4.ip_forward=1


Now what I need to do is to be able to access the IP camera from the inet.

So I have tried adding IPTables:

iptables -t nat -A PREROUTING -i wlan0 -d 192.168.1.71 -p tcp --dport
5555 -j DNAT --to 192.168.70.140:80

Now this should allow me to access the camera by pointing a web
browser to the real world public ip on port 5555, however I get page
cannot be displayed.


I have verified that:

1. That camera is accessable from the Ubuntu computer via web browser and ping
2. tcptrack sees the incoming connections at wlan0 but nothing on eth0 so I think the problem is with the rule. Tcptrackoutput:
Client Server State Idle Speed
118.92.xx.55:58674 192.168.1.71:80 RESET 1s 0 b/s
118.92.xx.55:58673 192.168.1.71:80 RESET 1s 0 b/s
118.92.xx.55:58676 192.168.1.71:80 RESET 1s 0 b/s

Not sure about "RESET" state? This bad?


Various people have suggsted I may need to modify conntrack and others
have suggested I may need a second rule.



Can anyone please help?