For the MX series in routed mode, you can enable VLANs in the Addressing and VLANs tab.  Once you have done this you can assign an access VLAN, or a trunk of multiple VLANs to each LAN port.  If you also set up IP addresses for the VLANs then you can route between them.   So although you cannot create a router port (in the traditional Cisco sense), you effectively can as you can have 24 VLANs with 24 IP addresses/subnets and apply one to each LAN port of the MX250.   ... View more