BGP Looking Glass List: Cogent, Lumen, NTT, HE and More
Verified links to the official looking glasses of Arelion, Lumen, Cogent, NTT, Hurricane Electric, Tata, Zayo, Verizon and Orange, plus the RIPE and PCH route collectors.
A looking glass is a web page where a network operator lets anyone run a command on one of its own routers: a ping, a traceroute, or a BGP lookup that shows how that network reaches a given address. It answers a question no tool on your own machine can: what does the path look like from inside someone else's network?
Official looking glasses of the major networks
Every link below was checked on 26 September 2026 and answered with the operator's own looking glass. Addresses change when networks rebrand, which is why so many lists online point to dead pages.
| Network | ASN | Looking glass |
|---|---|---|
| Arelion (formerly Telia Carrier) | AS1299 | lg.twelve99.net |
| Lumen (formerly Level 3, CenturyLink) | AS3356 | lookingglass.lumen.com |
| Cogent | AS174 | cogentco.com/en/looking-glass |
| NTT | AS2914 | gin.ntt.net |
| Hurricane Electric | AS6939 | lg.he.net |
| Tata Communications | AS6453 | lg.as6453.net |
| Zayo | AS6461 | lg.zayo.com |
| Verizon Business | AS701 | verizon.com/business |
| Orange (OpenTransit) | AS5511 | looking-glass.opentransit.net |
Route collectors: the view from many networks at once
An operator's looking glass shows one network's view. Route collectors gather the BGP tables of hundreds of networks, so they answer a broader question: is this prefix announced, by whom, and along which paths?
- RIPE RIS looking glass: the routes seen by the RIPE NCC's collectors around the world.
- PCH looking glass: routers of Packet Clearing House at internet exchanges around the world.
When a looking glass is the right tool
- A destination is slow only for some users. Trace to it from the transit providers your users sit behind and see whether one of them takes a detour.
- You changed a BGP announcement. Check from several networks that your new prefix is visible, and with the AS path you expect.
- A provider blames the other side. A traceroute from inside their own network, run from their own looking glass, settles where the path goes wrong.
What a looking glass will not tell you
Looking glasses run on core routers in data centres. They show how a backbone reaches an address, not what a user on a home connection experiences. They are also deliberately limited: few commands, a handful of probes, and rate limits that stop you from measuring anything over time. And each one only shows one network, so comparing providers means opening a dozen different pages with a dozen different forms.
Traceroute from 35 locations at once
TraceMapper fills that gap from the other side: it runs a traceroute to your destination from our servers and from 35 measurement locations in 31 countries, puts every hop on a map with its latency, packet loss and network (AS), and lets you compare the paths or re-run them on a schedule. For the BGP side, our ASN lookup and BGP viewer shows a prefix's origin, its upstream providers and the AS paths seen by the RIPE RIS collectors, without leaving the page.