OSPF DEFAULT ROUTES

RouterOS Forwarding Protocols
1

Have one mikrotik that is fed by two different incoming interfaces that both ultimately go back to the net.

One interface has the default route on it to its neighboring mik.

How I get packets coming in the second interface to go back out the second interface also.

Do I have to aggregate the second stream into a single subnet and use a routing mark to direct them to
the second ‘default’ route?

Can I automagically have any packet coming in one interface go out the same interface?

Do I do this by marking them as they come in the interface so they can be directed to go out the same
interface on the way back?

How does one redirect packets to different interfaces (all leading to the net) without a default routing scheme?

Seems like any effort to do source routing ends up using packet marks to do destination default routing anyhow, is that so?

Thanks Homer
Lightlink Internet

2

This is doable and by reading up on the wiki and underlying linux chains stuff you will be able to.
Mangle mark all connections coming in from the other interface, then you can pre or post route change the marked connections going out again.

I am only doing pure routing in the isp space.
For me this is an end customer question but as you se it is doable.

3

I have similar setup:

1 chain=prerouting action=mark-routing new-routing-mark=10.45.6.0
passthrough=yes src-address=10.45.6.0/24 in-interface=LakeStreet Bridge
log=no log-prefix=“”

2 chain=prerouting action=mark-routing new-routing-mark=10.45.4.0
passthrough=yes src-address=10.45.4.0/24 in-interface=LakeStreet Bridge
log=no log-prefix=“”

3 chain=prerouting action=mark-routing new-routing-mark=10.45.5.0
passthrough=yes src-address=10.45.5.0/24 in-interface=LakeStreet Bridge
log=no log-prefix=“”

Then I setup default routes depending on the routing mark you created above
NATOUT.PNG
Check out this post: http://forum.mikrotik.com/t/two-subnet-two-default-gateway/88976/1

4

You can configure VRF on each interface, and with some route rules you can handle easily what you’re trying to do.