redirect traffic based on destination port to another interface

[Julian Elischer]

Rudy Setiawan wrote:
> On 8/2/07, Julian Elischer <julian at elischer.org> wrote:
>> Rudy Setiawan wrote:
>>> Hi,
>>>
>>> I am trying to do a traffic redirection based on destination port to
>>> another interface/gateway.
>>> Currently, I have a freebsd box that does simple NAT and an Internet connection.
>>> I am planning to install another internet connection and use the same
>>> box to do some traffic redirection.
>>>
>>>
>>> INTERNET1 -------- freebsd box ------- INTERNET2
>>>                                  |
>>>                                  |
>>>                        Local Area Network
>>>
>>> LAN = 192.168.10.0/24 with interface em0
>>> INTERNET1-GW = x.x.x.1 with em1
>>> INTERNET2-GW = y.y.y.1 with rl0
>>>
>>> My goal is to redirect any ssh traffic to INTERNET2-GW and I assume
>>> that if it can be redirected through INTERNET2-GW then the packets
>>> return will go through INTERNET2-GW also.
>>>
>> no, unless you first NAT the packets with the address of that interface.
>> (otherwise the packets will come back through your primary network).
>> if yo have cheep dlink or linksys or whatever DSL routers or whatever with NAT
>> on them then you can use that successfully and just use ipfw 'fwd' rules to select the interface to use.
> 
> I see, hmm are you suggesting that the linksys should be placed
> between the freebsd firewall and the internet? Then do a ipfw fwd
> rules to in freebsd to select which interface to go and linksys will
> do all the NAT-ing for those packets respectiveily right?

exactly

> 
> Thank you.
> 
> Regards,
> Rudy