topic Re: ISE - Routing Multiple Interfaces in Network Access Control

ISE - Routing Multiple Interfaces

llomjaria — Tue, 23 Jan 2024 11:37:25 GMT

Hi,

I have ISE medium deployment. 2 PAN & MnT and 2 PSNs.

I have configured BYOD and Posture on PSNs. I configured Gi 1 interface with different IP address which should be used for BYOD and Posture portals.

My question is regarding routing. How ISE handles traffic that comes on Gi1 interface? Will it respond with the same interface or it will use Gi0?
How should I configure routing ?

In some cases NADs and users are in same subnet, so I cannot configure different routes for NADs and users.

Re: ISE - Routing Multiple Interfaces

Aref Alsouqi — Tue, 23 Jan 2024 11:48:19 GMT

ISE by default routes back the traffic out of the same interface where the traffic was received on.

Re: ISE - Routing Multiple Interfaces

llomjaria — Tue, 23 Jan 2024 11:53:48 GMT

Thanks for the reply!

Here is my current configuration:

ise-psn-1/admin#show ip route

Destination Gateway Iface
----------- ------- -----
169.254.4.0/24 0.0.0.0 cni-podman2
default 172.25.4.1 eth0
169.254.2.0/24 0.0.0.0 cni-podman1
172.25.4.0/24 0.0.0.0 eth0 - Radius/MGMT
172.25.24.0/24 0.0.0.0 eth1 - For Portals

Do I need to add static route: ip route 0.0.0.0 0.0.0.0 gateway 172.25.24.1 - for ISE to users traffic?

Re: ISE - Routing Multiple Interfaces

Aref Alsouqi — Tue, 23 Jan 2024 12:53:24 GMT

No I don't think so, as that network is a connected network to ISE. However, if you want to configure multiple default routes then yes.

Please refer to ip route section in this guide:

Cisco Content Hub - Cisco ISE CLI Commands in Configuration Mode

Re: ISE - Routing Multiple Interfaces

fcavalcanti — Fri, 13 Mar 2026 08:58:17 GMT

Hi Aref

I can see this is the behavior (via packet capture), but I'm trying to find official documentation that states this.

Do you have any?

Thanks

Re: ISE - Routing Multiple Interfaces

Aref Alsouqi — Wed, 01 Apr 2026 10:01:16 GMT

I'm sorry but I don't believe I have any documentation at handy talking specifically about that behaviour.