Just tried on 1.2.7 , VyOS lacks connection marking.
Seems like something like below isn’t implemented:
Note a packet mark is applied to skbuf object of the packet, and is lost when packet is sent out
A connection mark is a marking in conntrack table, which remains in place
Setting table on in-eth0 ,1 and 2 is useless, as this packet should be routed out on your LAN interface. If tables tables 100 101 102 don’t have entries for connected networks, you only break extra things
Route table selection should be done on LAN-IN
Also setting packet mark on in-eth0 ,1 and 2 is useless. It only affects packets towards your internal server, not return traffic
Ugly workaround:
Make your webserver listen on 3 ports, map each wan interface to a different port. Then for return traffic , do PBR on source port
WAN1 nat 80->81
WAN2 nat 80->82
WAN3 nat 80->83
The use PBR rules on LAN-IN:
source=webserver sourceport=81 , use table 101
source=webserver sourceport=82 , use table 102
source=webserver sourceport=83 , use table 103