Looking Glass servers (LG servers) are
server
Server may refer to:
Computing
*Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients
Role
* Waiting staff, those who work at a restaurant or a bar attending customers and su ...
s on the
Internet
The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices. It is a '' network of networks'' that consists of private, pub ...
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 computer programming and software development, debugging is the process of finding and resolving '' bugs'' (defects or problems that prevent correct operation) within computer programs, software, or systems.
Debugging tactics can involve in ...
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 or between or across multiple networks. Broadly, routing is performed in many types of networks, including circuit-switched networks, such as the public switched telephone netw ...
information. Essentially, the
server
Server may refer to:
Computing
*Server (computing), a computer program or a device that provides functionality for other programs or devices, called clients
Role
* Waiting staff, those who work at a restaurant or a bar attending customers and su ...
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 services for accessing, using, or participating in the Internet. ISPs can be organized in various forms, such as commercial, community-owned, non-profit, or otherwise private ...
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 th ...
s (NSPs), and
Internet exchange point
Internet exchange points (IXes or IXPs) are common grounds of IP networking, allowing participant Internet service providers (ISPs) to exchange data destined for their respective networks. IXPs are generally located at places with preexisting ...
s (IXPs).
Implementation
Looking glasses are web scripts directly connected to routers' admin interfaces such as
telnet
Telnet is an application protocol used on the Internet or local area network to provide a bidirectional interactive text-oriented communication facility using a virtual terminal connection. User data is interspersed in-band with Telnet control i ...
and
SSH
The Secure Shell Protocol (SSH) is a cryptographic network protocol for operating network services securely over an unsecured network. Its most notable applications are remote login and command-line execution.
SSH applications are based on ...
.
These scripts are designed to relay textual commands from the web to the router and print back the response. The are often implemented in
Perl
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offici ...
PHP
PHP is a general-purpose scripting language geared toward 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
Python may refer to:
Snakes
* Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia
** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia
* Python (mythology), a mythical serpent
Computing
* Python (pro ...
,
and are publicly available on
GitHub
GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking, software feature requests, task management, continuous ...
.
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 makes ...
(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 were small and old, having last been updated in the early 2000's.
See also
*
Autonomous system (Internet)
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 ...
*
Internet backbone
The Internet backbone may be defined by the principal data routes between large, strategically interconnected computer networks and core routers of the Internet. These data routes are hosted by commercial, government, academic and other high-ca ...
References
{{Reflist
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 nonprofit organization responsible for providing operational support and security to critical internet infrastructure, including Internet exchange points and the core of the domain name system. ...
br>
Looking Glass serversaround the world.
Looking Glass server source codeClickable map of known Reverse Lookup and Looking Glass servers in the worldLooking 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 ro ...
.
IPv4 and IPv6 BGP Looking Glassesat BGP4.as
BGP Looking Glass linkscollection at LookinGlass.org
CSpace Hostings Looking Glassa Network Service Providers looking glass example.
* RFC 8522: Looking Glass Command Set
Servers (computing)