If I have several Interfaces with different subnets (+vlans), all managed by RouterOS DHCP. What is the default behaviour of RouterOS when it comes to routing between those networks, given that RouterOS is the Default Gateway for all networks? My initial tests show that they are separated. I can’t ping machines in other Networks. Is that as expected, or just an artifact of my newbee configuration?
Default action is to route between all subnets. Unless you have some routing filters.
If there’s firewall config, then depending on rules traffic between subnets might be blocked.
Many devices, connected to networks, run their own firewall (e.g. Windows PCs) and that firewall often blocks traffic to device if it is originating from outside of own subnet.
Without knowing any details about your setup it’s hard to know which of the items above is blocking traffic in your case.
Very rude to force us to guess and what your config may or may not entail.
Minimum requirements is for the config posted and if complex network a network diagram.
What do you want to happen is more relevant
post config
/export file=anynameyouwish (minus router serial number, any public WANIP information, keys etc.)