Hello. I have a switch L3 that connects to two ISPs. The routing protocol used is BGP (one ISP is configured with a neighbor weight of 100 and the other is left by default). There is a route-map applied for the two of the ISP that only allows the default route in. I would like to test if I have internet connectivity using the backup ISP, but I cannot bring down any interface or change the configuration, due the fact that this is a production network. Is there a way I can force my tracert or ping to go through the secondary ISP to test the connectivity through it?
you can use PBR = Policy Based Routing
access-list 15 permit host x.x.x.x
route-map PBR permit 10
match address 15
set ip next-hop <Secondary-ISP-next-hop>
on internal interface like SVI interface Vlan 50 you apply
interface Vlan 50
ip policy route-map PBR
Note : PBR works only on the incoming direction so it needs to be applied on internal interface.
In this way a single specific host can test the backup path in the upstream direction.
Warning: I supposed you are not doing NAT on your L3 switch but before.
So the x.x.x.x address should be a public address.
To avoid to impact all traffic use a static NAT entry on device performing NAT
Hope to help