BGP Route Servers – Insight Into Your Subnets

When you have multiple internet providers, how do you really know what’s going on with your subnets? There are looking glasses (web based interfaces), which give you insight into a providers BGP tables. You can also get BGP info via route servers. These are generally routers that you can telnet into and issue show ip bgp commands. You can often get more detail this way. One of the down sides to this is that a BGP router will only advertise his best route to other peers. If your subnet comes from multiple sources directly to him, he will pick which subnet is the best path and advertise that NLRI to his neighbors. This is fine and is the way the internet functions. If I want to verify all of my direct peers are accepting and advertising my routes, this can sometimes be a problem. Like with Sprint. Sprint has a terrible looking glass (ping and traceroute only) and no direct route servers. If the route servers you hit have already chosen a better path upstream somewhere you may not see your Sprint advertised addressing. Some remarkable route server’s I’ve just found are the ones at the University of Oregon(http://www.routeviews.org)…of all places…heh. These guys have great connectivity and they house live information from LOTs of carriers. Give them a peek. They seem to have some other tools on their page that could be useful.