Using ip sla and eem for tracking a route

In ths post we will  look at a means for tracking a default route learned by ospf and generation of a syslog alert for when  the route disappears

The cisco EEM and IP SLA are being together to clear our route-table. In the core network, we have 2 exits one path being preferred by ospf-metrics


1st we write a simple IP SLA ,  this is the heart of our check ;

!
ip sla 200
 icmp-echo 10.10.11.254
 frequency 3
 timeout 600
 threshold 100
!

Next we active it & set a track ;

!
ip sla schedule 200 start-time now life forever
!
track  200 ip sla 200
!

Finally we build a  cisco eem applet that will generates a log msg if the gateway is lost;

!
event manager applet Default_Gone
 event track 200 state any
 action 1.0 syslog msg "ping to outside gw has died, ospf-neighbor is probably gone or down"
!

You can use other  action  items like reset the router ospf or clear ospf neighbor or install  another path route.

Ken Felix
Freelance Network/Security Engineer
kfelix  -----a----t---- socpuppets ---dot---com

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