Changing outbound NAT IP

Hey guys,
For various reasons I need to set something for work in a specific yet none conventional way.

Basically, my box has an IP and that IP has an IP range routed to it. The VM is running with NATed access to the internet. The needed ports are fwded to the VM. All of that is working fine.

However, the server is sourcing outbound connections from the primary IP. Not the IP NATed to it. (Since it is "closest" to the internet and that is default behavior.)

I need to override that default behavior to originate the connections from one of the IPs in the range.

I've add an ip route;
/sbin/ip route change default dev em1 src 8.8.80.109

When I originate a connection from the host hypervisor it will originate from the desired IP. However the NATing seems to happen prerouting, so it is not using the desired source IP.

Is there a way to get the system to NAT this VM via em1:0 addr:8.8.80.109 instead of the default?


em1 inet addr:8.8.116.251 Bcast:8.8.116.255 Mask:255.255.255.0


em1:0 inet addr:8.8.80.109 Bcast:8.8.80.109 Mask:255.255.255.255