Looking Glass servers (LG servers) are servers on the

Internet The Internet (or internet) is the Global network, global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a internetworking, network of networks ...

running one of a variety of publicly available Looking Glass software implementations. They are commonly deployed by autonomous systems (AS) to offer access to their routing infrastructure in order to facilitate

debugging In engineering, debugging is the process of finding the Root cause analysis, root cause, workarounds, and possible fixes for bug (engineering), bugs. For software, debugging tactics can involve interactive debugging, control flow analysis, Logf ...

network issues. A Looking Glass server is accessed remotely for the purpose of viewing

routing Routing is the process of selecting a path for traffic in a Network theory, network or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched ...

information. Essentially, the server acts as a limited, read-only portal to routers of whatever organization is running the LG server. Typically, Looking Glass servers are run by autonomous systems like

Internet service provider An Internet service provider (ISP) is an organization that provides a myriad of services related to accessing, using, managing, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, no ...

s (ISPs),

Network Service Provider Network Service Provider (NSP) is one of the roles defined in the National Information Infrastructure (NII) plan, which governed the transition of the Internet from US federal control to private-sector governance, with an accompanying shift from t ...

s (NSPs), and

Internet exchange point Internet exchange points (IXes or IXPs) are common grounds of Internet Protocol, IP networking, allowing participant Internet service provider, Internet service providers (ISPs) to exchange data destined for their respective networks. IXPs are ...

s (IXPs).

Implementation

Looking glasses are web scripts directly connected to routers' admin interfaces such as

telnet Telnet (sometimes stylized TELNET) is a client-server application protocol that provides access to virtual terminals of remote systems on local area networks or the Internet. It is a protocol for bidirectional 8-bit communications. Its main ...

and SSH. These scripts are designed to relay textual commands from the web to the router and print back the response. They are often implemented in

Perl Perl is a high-level, general-purpose, interpreted, dynamic programming language. Though Perl is not officially an acronym, there are various backronyms in use, including "Practical Extraction and Reporting Language". Perl was developed ...

PHP PHP is a general-purpose scripting language geared towards web development. It was originally created by Danish-Canadian programmer Rasmus Lerdorf in 1993 and released in 1995. The PHP reference implementation is now produced by the PHP Group. ...

, and Python, and are publicly available on

GitHub GitHub () is a Proprietary software, proprietary developer platform that allows developers to create, store, manage, and share their code. It uses Git to provide distributed version control and GitHub itself provides access control, bug trackin ...

Security concerns

A 2014 paper demonstrated the potential security concerns of Looking Glass servers, noting that even an "attacker with very limited resources can exploit such flaws in operators' networks and gain access to core Internet infrastructure", resulting in anything from traffic disruption to global

Border Gateway Protocol Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the Internet. BGP is classified as a path-vector routing protocol, and it ...

(BGP) route injection. This is due in part because looking glass servers are "an often overlooked critical part of an operator infrastructure" because it sits at the intersection of the public internet and "restricted admin consoles". As of 2014, most Looking Glass software was small and old, having last been updated in the early 2000's.

References

External links

Source code for the *original* Multi-Router Looking Glass (MRLG) by John Fraizer
@ OP-SEC.US *

Packet Clearing House Packet Clearing House (PCH) is the international organization responsible for providing operational support and security to critical Internet infrastructure, including Internet exchange points and the core of the Domain Name System. The organiz ...

br>Looking Glass servers
around the world.
Looking Glass server source code

Clickable map of known Reverse Lookup and Looking Glass servers in the world
{{Webarchive, url=https://web.archive.org/web/20080908065915/http://www.caida.org/research/routing/reversetrace/ , date=2008-09-08
Looking Glass Wiki
- List of hundreds of Looking Glass servers, sorted by

Autonomous System Number An autonomous system (AS) is a collection of connected Internet Protocol (IP) routing prefixes under the control of one or more network operators on behalf of a single administrative entity or domain, that presents a common and clearly defined rou ...

.
IPv4 and IPv6 BGP Looking Glasses
at BGP4.as
BGP Looking Glass links
collection at LookinGlass.org
CSpace Hostings Looking Glass
a Network Service Providers looking glass example. * RFC 8522: Looking Glass Command Set Servers (computing)

Implementation

Security concerns

See also

References

External links