sys db snat.hosttraffic

When the host (including bigd) generates traffic, it uses the host (linux) route table to pick the appropriate src IP address for the destination IP. If that src IP address is a tmm self-IP, then the packet is passed into tmm.

If tmm has a different view of the route to the destination IP (due to dynamic routing information, or different routing metrics when there are multiple possible routes), then the selected src IP may not be optimal, or may even fail to reach the destination.

When snat.hosttraffic is enabled, tmm can look at the host-sourced traffic, and then SNAT the src IP to the best src IP (which can change the egress vlan) based on the tmm routing table, and ignore the original host src IP as determined by the host routing table.