trying to understand NAT mode

[chino]

When keepalive is setup to nat to different backends (that can be on different hosts) how does the target host know to properly flip the source ip back to the vip address when replying? From observation the host seems to be directly returning the packets using it's own source address.

Curious if this feature was used for some type of proper Direct Server Return setup?

Thanks.

[panpan0000]

keepalived/lvs will not do SNAT, but only DNAT.
you will have to achieve snat by yourself.
example, on the real server node , set the default gateway to the VIP.