How can I make RouterOS respond to packets through the interface they came from?

Question

Mikrotik

Good afternoon!
1. There are WAN 1 and 2, switching using check-ping to the provider's gateway.
When WAN 1 is active, the external IP of the second is not pinged.
2. In addition, this RouterOS (6.xx) serves as an L2TP server for the remote office. When only one tunnel is enabled between WAN 1 of the main office and the remote one, then everything is fine, once you turn on the second tunnel to WAN 2, the first one connects and immediately falls off. The second one just doesn't work.
Secrets, dynamic routes, addresses are different for two tunnels.
I attribute this to the fact that ROS always responds to the default GW, even if the request did not come to it.
I read that you need to somehow mark something and then mangle, but I'm not strong in this.
I will be glad if you help.

Answer 1

hello
On the mangle tab, you need to create prerouting rules with the "mark routing" action and any name. The rule should catch the traffic that you need. For example, if the connection came to Wan2, then you need to answer to the Wan2 gateway. To do this, in the / ip route section, create a rule with a distance less than the default one and instead of the network to which to root, select 0.0.0.0/0, Wan2 gateway and in the brand field, select your brand.