Forgive me if I'm not using the correct terminology here but I'm on a Juniper MX204 router, call it router A. I'm receiving full table from my ISP. I do a show route, i.e. show route 1.1.1.1 and I get one prefix back.
show route 1.1.1.1
inet.0: 811234 destinations, 811234 routes (811190 active, 44 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both
1.1.1.0/24 *[BGP/170] 1d 19:42:09, localpref 100
AS path: 7473 6453 13335 I, validation-state: unverified
> to TRANSIT_IP_HERE via xe-0/1/1.0
Cloudflare, and the real network that is prompting this question, is multihomed. As far as I know about how BGP works the router receives all of the routes to 1.1.1.0/24 from the transit provider and selects the 'best' one to put into the FIB (based on a multitude of criteria, AS path length being the main one).
How can I show all of the AS paths for a network recieved from a transit provider, including those that were not chosen by BGP?
What I'm really trying to troubleshoot is a prefix which I'm multihoming. While I'm advertising the prefix to transit A and transit B I have a feeling transit B is filtering upstream. The show route statements only contain transit A but even in 1.1.1.0/24's case it also only shows one (the "best" AS-Path). I'm hopping to a few random internet routers and I want to prove that I'm not even receiving a route at all through transit B's.
show bgp summary
and see if you are getting dramatically fewer routes from them, or only missing a small number. That might help them troubleshoot.