Public looking glass servers worth bookmarking
Most large carriers and several research projects run public looking glasses. These are the ones network engineers reach for first.
- Hurricane Electric (lg.he.net): the best-known public looking glass, with routers across every region.
- Arelion (formerly Telia Carrier): a Tier 1 backbone with a global looking glass.
- NTT: Tier 1 operator with looking glass access across its global network.
- Lumen: the former Level 3 backbone, one of the largest transit networks.
- Cogent: Tier 1 carrier with a public looking glass across its footprint.
- RIPE RIS and RIPEstat: the RIPE NCC's route collectors, queryable through a web interface, with history.
- University of Oregon Route Views: the long-running academic route collector project.
Availability and features change over time, so if one server is down or missing a location, try another. The point is the vantage, not the vendor.
Looking glass vs ASN lookup: which do you need?
A looking glass answers routing questions: how a prefix propagates, which paths traffic takes, whether an announcement reaches a region. An ASN lookup answers ownership questions: which network operates an IP, what the organization is called, and whether it is a hosting provider or a consumer ISP. If your real question is "who owns this IP address in my logs," you do not need router output, you need Abstract's free ASN Lookup tool.
For scoring traffic in your own application, the same answer is available programmatically: Abstract's IP Intelligence API returns the ASN, its type, and security flags such as is_hosting and is_vpn for any IP, one request per check.
Frequently Asked Questions
What is a BGP looking glass?
A BGP looking glass is a public, read-only interface into a network operator's routers. It lets anyone run route, ping, and traceroute queries from that network's point of view, which is essential for diagnosing routing problems you cannot see from your own side.
Are looking glass servers free to use?
Yes. Operators publish them as a public service to make routing issues easier to diagnose. They are read-only, so queries cannot change anything on the router.
What is the difference between a looking glass and traceroute?
Traceroute shows the path packets take from your machine. A looking glass runs queries from inside another network, so it shows routes and paths as that network sees them, which is often where the actual problem lives.
How do I find out which ASN announces a prefix?
Run a BGP query for the prefix in a looking glass and read the origin ASN at the end of the AS path, or enter any IP from the range into an ASN lookup tool to get the operator's name and type instantly.
Why do carriers run looking glasses?
Because routing problems are two-sided. Giving peers and customers a self-serve view of their routing tables cuts support work and speeds up debugging for everyone involved.
