Re: Networking Question

["Jonathan A. Kollasch" <jakllsch%kollasch.net@localhost>]

On Thu, Dec 19, 2013 at 10:57:10PM +0100, Konrad Neuwirth wrote:
> Dear reader, 
> 
> I have a question that has me stymied. We have a NetBSD 6.1 system that is 
> connected to multiple networks; two of them are internet uplinks. One of them 
> has low bandwidth but fixed IP numbers that we need to have services run on 
> (and those services are actually on another host and we just do port 
> forwarding). The other is the high bandwidth link, but with a dynamic IP 
> number. 
> 
> I'm trying to get my head around how to properly configure this, but can't 
> get it to work. Code to have multiple default gateways seems to no longer be 
> there. But how can I have traffic that originates on one interface (because 
> it comes in via that one connection) be routed back correctly via the 
> low-bandwidth link, whereas other internet traffic goes the other way? 

You'll need to use some form of source-based routing.
That's implemented by the likes of pf(4)/ipf(4)/npf(4)/srt(4).