A Looking Glass is a web front end giving limited access to a router or route-collector/server for:
- Viewing the BGP table
- Allowing IXP members to verify their outbound BGP policies
- Viewing individual paths
- Checking traceroute and ping to destinations
- Checking RPKI status
Note: some network operators use the term “Router Proxy” instead of the industry standard “Looking Glass” name. They are one and the same thing.
There are several Looking Glass implementations:
- Birdspy (only for bird)
Some operators (network and IXP) write their own implementations to match their particular requirements. Here is an example of the public looking glass that SEACOM make available to the global Internet community:
Public Looking Glasses
PeeringDB entries for every AS holder will normally (and are encouraged to) document how to access the operator or IXP's Looking Glass. A common entry point in the past was www.traceroute.org but that does not seem to have been updated recently.
One of the most popular looking glasses globally is RouteViews operated by the RouteViews team at the University of Oregon. This has 36 locations around the globe and a large number of BGP feeds terminating at the various collectors globally.
The other commonly used Looking Glass is bgp.he.net which gives Hurricane Electric's perspective of the global internet as seen from all their points of presence around the world.
Using Looking Glasses
The use of Looking Glasses to ascertain routing information and help with troubleshooting is covered elsewhere in the Toolbox.