Enforce-as-first disable config Causing Route Leak @ Internet exchange

[Belinda Afari]

 Hello, The ISP I work for is having challenges with implementing the enforce-as-first disable configurations with an internet exchange. We have an RR setup for our BGP core. This command has been successfully applied to our Internet exchange connection on our upstream RR server routers. The new implementation is on one of our RR clients where the exchange is located. NB: as-path filters have been applied at the new exchange and all works fine until the configuration of the enforce-as command.

Any suggestions on a probable cause and solution?

[MHM Cisco World]

I review and make second review to your issue 

now I think that even if the first AS in AS-PATH is ignore still the NEXT-HOP issue, 
the BGP first criteria is NEXT-HOP reachable 
if it reachable then the path is accept 
if not reachable then the path is reject 


so TRY
neighbor x.x.x.x route-map NEXT in
!
route-map NEXT permit 10
match ip address  <<- this optional you will apply route-map first for only one prefix if success then we can apply it to all other prefix.
set ip next-hop peer address  

for IOS XR 

 route-policy NEXT
set next-hop peer-address