I configured an RB2011 with two WAN ports, eth1 and eth2. I setup masquerading and used eth1 as outgoing interface. This worked but if I changed the outgoing port to eth2 the packets still went out eth1. I would expect the packets to stop until I moved my WAN connection to eth2. This was among many strange issues in which all outgoing packets stopped at one time and I had to reload the software. I am using 6.18.

The goal at hand was to provide an office with their network connections thru a dedicated WAN (eth1) and then public traffic with hotspot thru another WAN interface (eth2).

Both eth1 and eth2 were setup as DHCP clients and would get an IP address. I could ping the default route from within the router but nothing past. I eventually had to put the router back to factory and only do masquerading thru eth1 for now.

Am I missing something here. I would not say I am an expert with Mikrotiks but have programmed many that work the way I think they should.

Be careful when doing masquerade/NAT: connections will be cached until they timeout. That is, if they are shown in "IP, firewall, connections" any packet related to them whon't be checked again against the masquerade/NAT rule... not even if you modify the rules.

In my experience, it's easier to setup that kind of deployments using a couple of devices/computers/virtual machines and defining specific NAT rules for each source IP of each test device. That way it's easy to find every connection and check whether it's still alive or not.