I have an RB750GL and two WAN’s. ISP1 is connected to eth1 and ISP2 is connected to eth2. LAN’s are connected to eth5. I have it setup so that all traffic goes out ISP1 and ISP2 is purely a failover link. What I want to do is to send only SMTP traffic from a specific internal subnet out ISP2 instead of ISP1. Below is what I tried from my research online and from this forum but for some reason I cannot get it to work. Any input is greatly appreciated. I come from the Cisco world and still learning the Mikrotik universe.
mangle rule:
chain=prerouting action=mark-routing new-routing-mark=SMTP passthrough=no protocol=tcp src-address=192.168.16.0/24 dst-address=0.0.0.0/0 dst-port=25
route rule:
dst-address=0.0.0.0/0 gateway=eth2 gateway-state=reachable distance=1 scope=30 target-scope=10
routing-mark=SMTP