Re: Public IP to Private IP

["Rob Sterenborg (lists)" <lists@sterenborg.info>]

On 01/27/2014 08:22 PM, Scott Mayo wrote:
> I am having some troubles getting my public IPs routed to my private IPs.
>
> Here is an example.
> Private IP of the main server with my IPTables:  192.168.0.1
> Public IP of the main server:  1.1.1.1
> I also have 1.1.1.2 and 1.1.1.3 as public IPs attached to the public nic.
> Domain name example.org is pointed to 1.1.1.2
>
> I am trying to get the following public IPs to Private IPs:
> 1.1.1.2 -> 192.168.0.2
> 1.1.1.3 -> 192.168.0.3
>
> If I am outside my network and go to example.org, it seems to work fine.
> If I am inside my network and go to 192.168.0.2 then it works fine.
> If I go to example.org from inside my network then it goes back to
> 192.168.0.1 instead of 192.168.0.2
>
> Maybe this does not have to do with IPTables even since it works with
> an IP, but I thought I would ask here.  I do not have an internal DNS
> server.
>
> Here are the rules that I have:
>
> IPTABLES -t nat -A PREROUTING -d 1.1.1.2 -p tcp -j DNAT
> --to-destination 192.168.0.2
> IPTABLES -t nat -A POSTROUTING -d 192.168.0.2 -j SNAT --to-destination 1.1.1.2
>
> Any suggestions would be appreciated.
> Thanks.

As already explained, NAT-ing packets from your LAN back into your LAN 
via the public IP (and receiving the answer packets) is a pain.

If you don't have split-DNS and don't want to install DNS, you might 
want to look into a reverse proxy (I have good experiences with Nginx).


--
Rob