Default gateways? How do they work? How many may we have on ISE?

[Gioacchino]

Hi,

I read few discussions on manipulating the routing table of ISE, especially when some servers, like RADIUS, are reachable out of a different interface. For such cases, somebody suggested to use static routes and even a second default gateway.

As ar as I know any routing table should have only one default gateway, because it's used when all the other route lookup fail.
How does the default gateway work in ISE?

In our case, we even three default gateways!

TIA, Gio

[MHM Cisco World]

Did you read cisco doc. I Shared?

Read last note in doc. You will know if you use both commands the behave of cisco device 

MHM

[Aref Alsouqi · Accepted solution]

The default-gateway entry applies to all interfaces as a last resort, however, the individual default routes (ip route) apply to each interface based on the config. From the link I shared previously:

Cisco Identity Services Engine CLI Reference Guide, Release 3.2 - Cisco ISE CLI Commands in Configuration Mode [Cisco Identity Services Engine] - Cisco

[Aref Alsouqi · Accepted solution]

All the routes that you add with the "ip default-gateway" and "ip route" will end up in the same routing table and will be managed by the same routing engine. The default gateway is the last resort and will be used if there is no other more specific static route added.

For instance in the example of the multiple remote guest subnets I gave before, if the traffic should come say from a 192.168.1.0/24 subnet, the route that will be used in that case would be the one defined in the "ip default-gateway".