Looking Glass server
Looking Glass servers are computers on the Internet running one of a variety of publicly available Looking Glass software implementations. A Looking Glass server (or LG server) is accessed remotely for the purpose of viewing routing information. Essentially, the server acts as a limited, read-only portal to routers of whatever organization is running the LG server.

Typically, publicly accessible Looking Glass servers are run by Internet service providers (ISPs) or Internet exchange points (IXPs).

External links
  Source code for the *original* Multi-Router Looking Glass (MRLG) by John Fraizer @ OP-SEC.US
 Packet Clearing House Looking Glass servers around the world.
 Looking Glass server source code
 Clickable map of known Reverse Lookup and Looking Glass servers in the world
 Looking Glass Wiki - List of hundreds of Looking Glass servers, sorted by Autonomous System Number.
 IPv4 and IPv6 BGP Looking Glasses at BGP4.as
 BGP Looking Glass links collection at LookinGlass.org