Sorry for the lack of response - I'm completing the topic now.
It's about handling incoming traffic
TO MikroTik from 2 ISP
I have added 2 default routing routes in 2 different tables:
/ip route/print detail where dst-address="0.0.0.0/0"
Flags: D - dynamic; X - disabled, I - inactive, A - active; c - connect, s - static, r - rip, b - bgp, o - ospf, d - dhcp, v - vpn, m - modem, y - copy; H - hw-offloaded; + - ecmp
0 As dst-address=0.0.0.0/0 routing-table=main pref-src="" gateway=x.x.x.x immediate-gw=x.x.x.x%vlan3730_WAN distance=1 scope=30 target-scope=10 suppress-hw-offload=no
1 As dst-address=0.0.0.0/0 routing-table=LTE pref-src="" gateway=y.y.y.y immediate-gw=y.y.y.y%vlan10_LTE distance=1 scope=30 target-scope=10 suppress-hw-offload=no
/routing/table/print
Flags: D - dynamic; X - disabled, I - invalid; U - used
0 D name="main" fib
1 name="LTE" fib
Mangle configuration is:
/ip firewall mangle
add action=mark-connection chain=prerouting connection-mark=no-mark in-interface=vlan10_LTE log=yes log-prefix=LTE_conn new-connection-mark=LTE_conn passthrough=yes
add action=mark-routing chain=output connection-mark=LTE_conn log=yes log-prefix=LTE_route new-routing-mark=LTE passthrough=yes
And finally, by pinging from the Internet to the address on the vlan10_LTE interface, the response is directed to the gateway in vlan3730_WAN - that is, the links work in the main routing table:
firewall,info LTE_conn prerouting: in:vlan10_LTE out:(unknown 0), connection-state:new src-mac a0:50:43:e5:11:02, proto ICMP (type 8, code 0), x.x.x.x->y.y.y.y, len 60
firewall,info LTE_route output: in:(unknown 0) out:vlan3730_WAN, connection-mark:LTE_conn connection-state:established proto ICMP (type 0, code 0), x.x.x.x->y.y.y.y, len 60
I have no idea what I'm doing wrong here
Thank you in advance for your help