I want to set up DHCP on more than one interface. I would like to pass the DNS servers from the WAN. Since this is a mobile Tik, the WAN and DNS could be anything. I want the user to be able to plug it into any ethernet provider (DSL, whatever) that uses DHCP, and the Tik to pick up those DNS servers and make them available via my LAN DHCP server(s).
How can I do this?
http://wiki.mikrotik.com/wiki/Manual:IP/DHCP_Client#Properties
add-default-route (yes | no; Default: yes) Whether to install default route in routing table received from dhcp server.
use-peer-dns (yes | no; Default: yes) Whether to accept the DNS settings advertised by DHCP Server. (Will override the settings put in the /ip dns submenu.
Then set up the router as a DNS server: http://wiki.mikrotik.com/wiki/Manual:IP/DNS, and hand out the router as the DNS server to your DHCP clients on the LAN.
That way the LAN users will always use the router for DNS, and the router itself will use whatever it gets via DHCP.