Thanks for the reply,
I have tried that and it's not working for me.
That is the only two mangle rules in place and just the one marked route active.
I can't ever get access unless there is an unmarked default route as well - which defeats the point of having a marked route.
Any other suggestions?
Compact export from newish install:
ros code
/interface ethernet
set 0 name=ether1-gateway
set 1 name=ether2-master-local
set 2 master-port=ether2-master-local name=ether3-slave-local
set 3 master-port=ether2-master-local name=ether4-slave-local
set 4 name=ether5-slave-local
/ip pool
add name=default-dhcp ranges=192.168.88.10-192.168.88.254
/ip dhcp-server
add address-pool=default-dhcp disabled=no interface=ether2-master-local name=default
/ip address
add address=192.168.88.1/24 comment="default configuration" interface=ether2-master-local network=192.168.88.0
/ip dhcp-client
add add-default-route=no comment="default configuration" dhcp-options=hostname,clientid disabled=no interface=ether1-gateway
/ip dhcp-server network
add address=192.168.88.0/24 comment="default configuration" dns-server=192.168.88.1 gateway=192.168.88.1
/ip dns
set allow-remote-requests=yes
/ip dns static
add address=192.168.88.1 name=router
/ip firewall filter
add chain=input comment="default configuration -ping" protocol=icmp
add chain=input comment="default configuration est input" connection-state=established
add chain=input comment="default configuration related input" connection-state=related
add action=drop chain=input comment="default configuration - drop incoming eth1" in-interface=ether1-gateway
add chain=forward comment="default configuration est forward" connection-state=established
add chain=forward comment="default configuration related forward" connection-state=related
add action=drop chain=forward comment="default configuration invalid forward drop" connection-state=invalid
/ip firewall mangle
add action=mark-connection chain=prerouting connection-mark=no-mark dst-address-type=!local new-connection-mark=MainPCConn src-address=\
192.168.88.0/24
add action=mark-routing chain=prerouting connection-mark=MainPCConn new-routing-mark=MainPC src-address=192.168.88.0/24
/ip firewall nat
add action=masquerade chain=srcnat comment="default configuration" out-interface=ether1-gateway
/ip route
add distance=1 gateway=192.168.2.1 routing-mark=MainPC