Hi Andrew, thanks for sharing your repo, it looks very relevant and I should be able to get it to do what I want with a slight tweak to the regex's. Hopefully the route-views collectors or some other ones I dig up will be able to adequately show at least 3 AS path hops through my regional provider to get to my AS/prefix. I really want to see AS paths where there are at least 2 different AS hops before my regional providers AS. This will help me feel good that the global partners of my regional ISP are re-advertising my prefix to their peers. Otherwise if the AS path only includes the first and second hop upstream I can only infer that the 2nd hop AS is accepting routes from the 1st hop AS (my regional ISP), but not that the 2nd hop AS is actually re-advertising the route to anyone else. thanks! -andy On Thu, Mar 29, 2018 at 7:51 AM, Andrew Wentzell <awentzell@gmail.com> wrote:
Hi all, I have an enterprise network and do not provide transit. In one of our datacenters we have our own prefixes and rely on two ISPs as BGP neighbors to provide global reachability for our prefixes. One is a large regional provider and the other is a large global provider.
Recently we took our link to the global provider offline to perform maintenance on our router. Nearly immediately we were hit with alerts
our prefix was unreachable and BGPMon alerted that nearly 80 AS's noted our route had been withdrawn. We were not unreachable from every AS, but we certainly were from some of the largest.
The root cause is that the our prefix is not being adequately re-distributed globally by the regional ISP. This is unexpected and we are working through this with them now.
My question is, how can I monitor global reachability for a prefix via
or any specific provider I use over time? Are there various route-servers I can programmatically query for my prefix and get results that include AS paths? Then I could verify that an "acceptable" number of paths exist
On Wed, Mar 28, 2018 at 7:22 PM, Andy Litzinger <andy.litzinger.lists@gmail.com> wrote: that this that
include the AS of the all the ISPs I rely upon. And what would an "acceptable" number of alternate paths be?
I did something similar a few years ago, by querying routeviews and validating AS paths using python and pexpect. You could adapt it for your use pretty easily. The code's here: