"Special" nating problem...
I'm having trouble on figuring out exactly how to do the following:
I'm trying to forward/route internal private traffic (e.g.: from one PC with IP 192.168.1.100) by using a router internal (br-lan) eth0 interface gateway (192.168.1.1) to a public server ip (188.8.131.52), which only accept connections coming from inside a ALG (Application Layer Gateway) interface, which is named: iptvwan; eth1 interface - 10.20.20.10.
The issue here is: i need that the ip 192.168.1.100 to be visible to the public server, from the iptvwan eth1 interface. I do NOT want to masquerade it - that's what i've got right now implemented (i don't want eth1 interface [10.20.20.10] changing the src ip of packets coming from 192.168.1.100 with it's own 10.20.20.10). I don't mind if there's a PAT...but i do need to keep the outside ip equal to the internal ip.
here it is a diagram of what i'm looking for: Attachment 4063
Anyway, here are some packets that i've captured on a thomson router, showing it working like i would like to implement:
obs: If you look carefully, you'll see that it looks like has if the private ip is talking directly to the public ip (and vice-versa) like if it was being routed.
note 1: Replace (dot) by a .
note 2: Since i haven't reached the 15 posts quota, i apologize but this is the only way i can post the above link
So, how can i do this? i'm a little bit confused on what type(s) of nat do i need, so to be able to replicate the above...do i need a:
- port restricted cone nat?
- nat reflection / hole punching?
- hairpin translation ?
- other ?
...and how can i implement this with iptables? do i need to forward/nat through loopback?
if someone could share some shed of light i would appreciate it.
btw: i'm trying to implement this on a draytek using a special/modified version of openwrt...