Hello,
I have a question regarding AS path prepend. I have an EBGP with a another customer and I am advertising all routes in my routing table to this BGP neighbour.
We are also learning several /24s from this customer and advertising those out to upstream carriers. The customer has come back to say they are also using several other ISPs to advertise these ranges out to internet therefore would like to check if we would allow AS Path prepend.
I have limited knowledge of AS PATH prepend therefore would like to know how can we achieve this or if in my config below is there anything that is blocking AS path prepend.
set protocols bgp group customers neighbor 2.2.2.2 description Customer-Transit
set protocols bgp group customers neighbor 2.2.2.2 local-address 2.2.2.1
set protocols bgp group customers neighbor 2.2.2.2 import CUST_ASCustomer-AS
set protocols bgp group customers neighbor 2.2.2.2 export CUST_ASCustomer-AS-export
set protocols bgp group customers neighbor 2.2.2.2 export default
set protocols bgp group customers neighbor 2.2.2.2 peer-as Customer-AS
set policy-options prefix-list customer_ASCustomer-AS 3.3.3.0/22
set policy-options policy-statement CUST_ASCustomer-AS term valid-prefixes from prefix-list-filter customer_ASCustomer-AS orlonger
set policy-options policy-statement CUST_ASCustomer-AS term valid-prefixes then local-preference 900
set policy-options policy-statement CUST_ASCustomer-AS term valid-prefixes then community set MY-transit-customer
set policy-options policy-statement CUST_ASCustomer-AS term valid-prefixes then accept
set policy-options policy-statement CUST_ASCustomer-AS then reject
set policy-options policy-statement CUST_ASCustomer-AS-export term transit-routes from protocol bgp
set policy-options policy-statement CUST_ASCustomer-AS-export term transit-routes from community MY-transit-route
set policy-options policy-statement CUST_ASCustomer-AS-export term transit-routes then community delete all-communities
set policy-options policy-statement CUST_ASCustomer-AS-export term transit-routes then accept
set policy-options policy-statement CUST_ASCustomer-AS-export term public-peering-routes from protocol bgp
set policy-options policy-statement CUST_ASCustomer-AS-export term public-peering-routes from community MY-public-peer
set policy-options policy-statement CUST_ASCustomer-AS-export term public-peering-routes then community delete all-communities
set policy-options policy-statement CUST_ASCustomer-AS-export term public-peering-routes then accept
set policy-options policy-statement CUST_ASCustomer-AS-export term private-peering-routes from protocol bgp
set policy-options policy-statement CUST_ASCustomer-AS-export term private-peering-routes from community MY-private-peer
set policy-options policy-statement CUST_ASCustomer-AS-export term private-peering-routes then community delete all-communities
set policy-options policy-statement CUST_ASCustomer-AS-export term private-peering-routes then accept
set policy-options policy-statement CUST_ASCustomer-AS-export then next policy
Please can someone advise how to make sure we are not filtering AS path prepend using above.