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 <awentz...@gmail.com> wrote: > On Wed, Mar 28, 2018 at 7:22 PM, Andy Litzinger > <andy.litzinger.li...@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 > that > > 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 route had been withdrawn.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 > this > > 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 > 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: > > https://github.com/awentzell/check-as-path >
