Interface address sourced packets go thru default gateway on another interface

[Steve Bertrand]

> As other contributors have suggested, if you really need source routing,
> use pf or similar for that. I believe ipf also supports route-to on the
> outbound.

Another solutions would be that if there is only a known subset of
networks sending you data over the leased line (such as a few /24's),
then you can just statically route these blocks back over that connection.

If not, as many others have said, it's policy based routing for you ;)

Steve