RouterOS v5.22 Unusual Behavior

RouterOS General
1

I’ve been experiencing some odd behavior in RouterOS v5.22:
The RouterBoard has two independent interfaces, and firewall rules to drop any forwarding between them.
ether1 - 192.168.1.1
ether2 - 192.168.2.1

By setting the gateway of a system connected to ether2 to 192.168.2.1, it is possible to ping 192.168.1.1 (ether1) even if ether1 is set to drop all pings on input. If ether2 is set to drop all pings on input though, ping no longer works.

It seems like both interfaces are listening with both IPs to a certain extent. Is this expected?

2

http://wiki.mikrotik.com/wiki/Manual:Packet_Flow

3

I’ve seen those diagrams before, but it still seems problematic.

Why is accessing the address of a different interface treated as input instead of forward, or as input on the interface which actually has that address?