We have a MT router with 3 NIC’s.
The first interface, Wireless, has a 10.x.x.163/24 address, which routes to our main wireless headend at 10.x.x.1.
The second interface, DSL, has a static 71.x.x.110/24 address, which goes to our backup DSL provider.
The third interface, Sonicwall, has a routable ip of 208.x.x.25/30, which connects to the customers sonicwall router at 208.x.x.26.
We have two default routes set, one with a metric of 10 to prefer the wireless path, the second with a metric of 20 for the dsl path.
Because we’re using the mikrotik as the DSL endpoint, anything behind it must be NAT’d to take the DSL routers ip address, so we have a srcnat rule that says that anything from 208.x.x.24/30 going out the DSL interface gets masqueraded.
Here’s what’s happening so far - when we disconnect either the dsl or wireless, the mikrotik fails over appropriately, so it can ping out to the internet through either path, and it seems to fail back properly too. However, the sonicwall behind it can’t ping out at all. It seems that the nat rule either isn’t right, or the outbound interface doesn’t do what I think it should, or something.
If someone could try and help out on this - I’d greatly appreciate it. Thanks!