OK, good news, everything is up and working.
As reviewing the whole thing, the scenario was:
Mikrotik router is handling 2 WANs and 1 LAN interface:
WAN1 has 10.4.14.1 as gateway
WAN2 has 10.33.52.1 as gateway
The router has two basic tasks:
1. Route all traffic through WAN1, except one specific destination IP that its being routed through WAN2.
2. The other task is to create a NAT. A server located inside LAN with IP 10.24.14.21 needs to be NATed with the public IP 10.33.52.242 at port 8080 but this must be done through WAN2 network.
I'm posting the final configuration. I'm pretty sure that some lines can be removed, so if you can help me with that I would be grateful:
Line 1: /interface ethernet
Line 2: set 0 arp=enabled auto-negotiation=yes cable-settings=default \
Line 3: disable-running-check=yes disabled=no full-duplex=yes l2mtu=16383 \
Line 4: mtu=1500 name=LAN speed=100Mbps
Line 5: set 1 arp=enabled auto-negotiation=yes cable-settings=default \
Line 6: disable-running-check=yes disabled=no full-duplex=yes l2mtu=16383 \
Line 7: mtu=1500 name=WAN1 speed=100Mbps
Line 8: set 2 arp=enabled auto-negotiation=yes cable-settings=default \
Line 9: disable-running-check=yes disabled=no full-duplex=yes l2mtu=16383 \
Line 10: mtu=1500 name=WAN2 speed=100Mbps
Line 12: /ip address
Line 13: add address=10.24.14.1/24 disabled=no interface=LAN network=10.24.14.0
Line 14: add address=10.4.14.2/24 disabled=no interface=WAN1 network=10.4.14.0
Line 15: add address=10.33.52.242/24 disabled=no interface=WAN2 network=10.33.52.0
Line 17: /ip firewall filter
Line 18: add action=accept chain=input disabled=no dst-address=10.33.52.242 dst-port=\
Line 19: 8080 in-interface=WAN2 protocol=tcp
Line 20: add action=accept chain=output disabled=no out-interface=WAN2 protocol=tcp \
Line 21: src-address=10.24.14.21 src-port=8080
Line 22: add action=accept chain=input disabled=yes dst-address=10.33.52.9 dst-port=80 \
Line 23: in-interface=WAN2 protocol=tcp
Line 24: add action=drop chain=input disabled=no in-interface=WAN2
Line 26: /ip firewall mangle
Line 29: add action=mark-connection chain=prerouting disabled=no in-interface=WAN1 \
Line 30: new-connection-mark=WAN1_connection passthrough=yes
Line 31: add action=mark-connection chain=prerouting disabled=no in-interface=WAN2 \
Line 32: new-connection-mark=WAN2_connection passthrough=yes
Line 33: add action=mark-routing chain=prerouting connection-mark=WAN1_connection \
Line 34: disabled=no in-interface=LAN new-routing-mark=to_WAN1 passthrough=yes
Line 35: add action=mark-routing chain=prerouting connection-mark=WAN2_connection \
Line 36: disabled=no in-interface=LAN new-routing-mark=to_WAN2 passthrough=yes
Line 37: add action=mark-routing chain=output connection-mark=WAN2_connection \
Line 38: disabled=no new-routing-mark=to_WAN2 passthrough=yes
Line 40: /ip firewall nat
Line 41: add action=masquerade chain=srcnat disabled=no src-address=10.24.14.0/24
Line 42: add action=masquerade chain=srcnat disabled=no out-interface=WAN2
Line 43: add action=masquerade chain=srcnat disabled=no out-interface=WAN1
Line 50: add action=dst-nat chain=dstnat disabled=no dst-address=10.33.52.242 \
Line 51: dst-port=8080 in-interface=WAN1 protocol=tcp to-addresses=10.24.14.21 \
Line 52: to-ports=8080
Line 53: add action=dst-nat chain=dstnat disabled=no dst-address=10.33.52.242 \
Line 54: dst-port=8080 in-interface=WAN2 protocol=tcp to-addresses=10.24.14.21 \
Line 55: to-ports=8080
Line 57: /ip route
Line 60: add disabled=no distance=2 dst-address=0.0.0.0/0 gateway=10.33.52.1 \
Line 61: routing-mark=to_WAN2 scope=30 target-scope=10
Line 62: add disabled=no distance=1 dst-address=0.0.0.0/0 gateway=10.4.14.1 scope=30 \
Line 63: target-scope=10
Line 64: add comment=IRIS disabled=no distance=1 dst-address=10.5.14.0/24 gateway=\
Line 65: 10.33.52.1 scope=30 target-scope=10
Here are some questions that need clarification:
Q.1
Line 15:
Do I need to set the specific IP (meaning the .242), because the public address that needs to be NATed is 10.33.52.242, or that's irrelevant? E.g can I set 10.33.52.4/24 with no impact?
Q.2
Lines 17-24:
The firewall rules are mandatory, or are there for security reasons?
Q.3
In the /ip firewall mangle section, I mangled almost everything! I guess that lines:
Line 29: add action=mark-connection chain=prerouting disabled=no in-interface=WAN1 \
Line 30: new-connection-mark=WAN1_connection passthrough=yes
Line 33: add action=mark-routing chain=prerouting connection-mark=WAN1_connection \
Line 34: disabled=no in-interface=LAN new-routing-mark=to_WAN1 passthrough=yes
are not needed?
Q.4
In the /ip firewall nat section, are all the rules needed here?
Q.5
Lines 60-61:
Do I have to set the distance in a higher value than the distance in line 62?
Thank you all for your support!