[wellylug] multiple gateways

[Nigel Roberts]

On Fri, 03 Dec 2004 at 10:38:28 +1300, Pete Black wrote:

> Can you clarify this please - when you say you want to respond to 
> traffic that comes in from two different gateways, do you simply mean 
> you have multiple interfaces on your machine?
> 
> Can you be more specific about your network setup, as the degree to 
> which linux's default arp, rp_filter etc. proc entries and route cache 
> will ruin your day depends very much on exactly what you are trying to do.
> 
> You can do just about any kind of 'smart' routing using iproute2 and 
> iptables, and the assertion that you can have only one default gateway 
> is technically not correct.
> 
> You can have only one default gateway per routing table. - it is 
> relatively easy simply to mark all packets entering via a given 
> interface and sending them to a specified route table which will enable 
> you to control which interface a packet leaves on based on the interface 
> it entered on etc. etc.

Yes sorry, I should have said one active default gateway per routing table.

This seems like a good reason to use multiple routing tables, but too
often people do this stuff as a work around for brokeness elsewhere. I
personally haven't had a use for them yet.

Regards,
Nigel