mult public conn/mult private conn routing

[steve at freeslacker.net]

Hello,

I am having a problem with setting up a box I just built for the dedicated purpose of being a freebsd router. Below is a diagram describing my physical setup:

ISP conn #1                            ISP conn #2
  |                                          |
  \  68.x.x.x/26          24.x.x.x/26       /
   -----------------_____-------------------
               fxp0|     |fxp1
                   |     |
                em0| ____|em1
                  /       \
192.168.0.1/24____|       |_____192.168.100.1/24

fxp0 is 3.2Mb/s down 256Kbp/s up and will be used by all normal hosts on em0
fxp1 is 3.2Mb/s down 450Kbp/s up and will be used by servers on em1

What I want to achieve is having all outbound traffic from em0 (192.168.0.1/24) use fxp0, and all outbound traffic from em1 (192.168.100.1/24) use fxp1. em0 and em1 should be able to talk to each other. The problem is that since defaultrouter="68.x.x.x" is specified in /etc/rc.conf all traffic gets routed out through fxp0. Also, since natd_interface="fxp0" is specified, all packets are nat'ed from either em0 or em1 through fxp0.

Is it possible to have natd on both fxp0 *and* fxp1 (i tried putting both natd_interface="fxp0" and natd_interface="fxp1" in /etc/rc.conf but this did not work)? Once a packet gets routed to fxp1, it just times out since the default route is atached to only fxp0.

I've read up on routed and ipfw, but do not see a way to tell fxp0 to use defaultrouter A, and tell fxp1 to use defaultrouter B. Do I have to run a routing daemon for this? (examples/suggestions would be appreciated)

Any ideas?

Steve Stremciuc