Chris Adams wrote on 11/02/2020 17:30: > Just curious what others do... I always assumed AS path filtering to > customer (and their downstream customers) AS was a standard best > practice.
It is. Then again, there exists every exception to the rule you can think of. If the exception has not been seen yet, we have not looked hard enough. => I.e. it depends. Is my answer. BCP is to not accept direct customer routes 'another provider's AS in the path'. If you can reach an agreement with the customer. You can agree to a >standardized< exception for this single customer. <= Your dice to roll. You are the customers upstream in this case. AS-path rewriting on the customers side of the eBGP connection is an option. If they remove $otherProviders ASN from the path before (re-)announcing the black-hole routes to you. So $customerASN is seen as the source when you receive the announcements. Chriztoffer