The current SNAT implementation has several limitations:
- SNAT source port has to be specified. It is not optional.
- SNAT source port range is not supported.
- SNAT for UDP is a one-way translation. No response packets
are handled (because conntrack doesn't support UDP currently).
- SNAT and REDIRECT can't work on the same connection.
Fixes#5489
PiperOrigin-RevId: 367750325
Toshi Kikuchi