'Reconnaissance', sometimes referred to as scouting, is the act of exploring (especially military or medical) to gain information. Often referred to as ''recce'' (UK and Australia,
pronounced ) or ''recon'' (U.S.), the associated formal
verb is ''reconnoitre'' (British spelling) or ''reconnoiter'' (American spelling). In informal English, both ''recce'' and ''recon'' are often also used as a verb.
It the
military term for the active gathering of information about an enemy, or other conditions, by physical observation. It is part of
combat intelligence. Compare to
counterintelligence and to
surveillance, which is passive gathering of information.
In
geology, the term refers to an "examination or survey of the general geological characteristics of a region". In
computer networking and security the term refers to an "exploration or enumeration of network infrastructure including network addresses, available communication ports, and available services."
Examples of reconnaissance include
patrolling by troops, ships,
submarines, or
aircraft, or by setting up
covert observation posts. Reconnaissance may also be carried out by
satellites or unmanned aircraft.
Network reconnaissance is typically carried out by a remote attacker attempting to gain informtion or access to a network he/she is not authorized or allowed.
Espionage is not normally considered to be covered by the term reconnaissance, as reconnaissance involves uniformed military forces operating ahead of the main force, opposed to non-combatant individuals behind the enemy lines.
Reconnaissance seeks to collect information about an enemy. This includes types of enemy units, locations, numbers, and intentions or activity. A number of acronyms exist for the information to be gathered – mainly coined by the US – including ''salt'' (size, activity, location, and time), ''salute'' (size, activity, location, unit, time, and equipment), ''sam & doc'' (strength, armament, movement, deployment, organization, and communications). Thus reconnaissance is a fundamental tactic which helps to build an intelligence picture.
Airborne reconnaissance

Reconnaissance photographs, such as this one of Soviet missile installations, played a key role in the
Cuban Missile Crisis in 1962.
Main articles: Surveillance aircraft
Airborne reconnaissance goes back to the early era of
ballooning. After the
French Revolution, the new rulers became interested in using the balloon to observe enemy manoeuvres and appointed scientist
Charles Coutelle to conduct studies using ''L'Entreprenant'', the first reconnaissance aircraft. The balloon found its first use in the , where in the
Battle of Fleurus the gathered information and the demoralizing effect on the Austrian troops ensured victory for the French troops.
The first use of airplanes in combat missions was by the
Italian Air Force during the
Italo-Turkish War of 1911-1912. On
23 October 1911, an Italian pilot flew over the Turkish lines in
Libya to conduct history's first aerial reconnaissance mission, and on
1 November 1911, the first ever aerial bomb was dropped on the Turkish troops in Libya.
On
16 October 1912 a
Bulgarian Albatros aircraft was used to perform Europe's first reconnaissance flight in combat conditions, against the Turkish lines on the
Balkan peninsula, during the
Balkan Wars of 1912-1913.
During the
First World War, photo reconnaissance was one of the early uses of the aeroplane. Aviators such as
Fred Zinn evolved an entire range of new flying and photography techniques to use the new technology in the equally new environment of
trench warfare.
Before the
Second World War the conventional wisdom was to use converted
bomber types for airborne photo reconnaissance. These bombers retained their defensive armament, which was vital since they were unable to avoid interception.
In 1939
Flying Officer Maurice Longbottom of the
RAF was among the first to suggest that airborne reconnaissance may be a task better suited to fast, small aircraft which would use their speed and high service ceiling to avoid detection and interception. Although this seems obvious now, with modern reconnaissance tasks performed by fast, high flying aircraft, at the time it was radical thinking. He proposed the use of
Spitfires with their armament and
radios removed and replaced with extra fuel and cameras. This led to the development of the
Spitfire PR variants. Spitfires proved to be extremely successful in their reconnaissance role and there were many variants built specifically for that purpose.
Immediately after World War II, long range aerial reconnaissance was taken up by adapted jet bombers – such as the
English Electric Canberra, and its American development, the
Martin B-57 – capable of flying higher or faster than the enemy. After the
Korean War,
RB-47 aircraft were used. These were at first converted B-47 jet bombers, but later these were purposely built RB-47 reconnaissance planes. They did not carry any bombs. They had large cameras mounted in the belly of the plane, and with a truncated bomb bay used for carrying
flash bombs.
The onset of the
Cold War led the development of highly specialized and secretive strategic reconnaissance aircraft, or
spy planes, such as the
Lockheed U-2 and its successor, the
SR-71 Blackbird (both from the
United States). Flying these aircraft became an exceptionally demanding task, as much because of the aircraft's extreme speed and altitude as it was because of the risk of being captured as
spies. As a result, the crews of these aircraft were invariably specially selected and trained.
Although much of this type of intelligence can now be gathered by
satellite photography and
unmanned aerial vehicles, manned reconnaissance aircraft still play a vital role on the modern battlefield.
Reconnaissance in force
Some military elements tasked with reconnaissance are armed only for self-defence, and rely on stealth to gather information. Others are well-enough armed to also deny information to the enemy by destroying their reconnaissance elements.
''Reconnaissance in force'' (RIF) is a type of
military operation used specifically to probe an enemy's disposition. By mounting an offensive with considerable (but not decisive) force, the commander hopes to elicit a strong reaction by the enemy that reveals its own strength, deployment, and other tactical data. In modern warfare, key weapon systems such as
surface-to-air missile batteries,
radar sites, artillery, and so forth can give their location away to everyone for miles around when actively fighting. The RIF commander retains the option to fall back with the data or expand the conflict into a full engagement.
''Reconnaissance by fire'' (or ''speculative fire'', 'spec fire') is a
tactic which applies a similar principle. When not trying to be stealthy, reconnaissance units may fire on likely enemy positions to provoke a reaction. In the
Iraq war, insurgents and
terrorists use a similar tactic, in which they brandish weapons or purposely draw suspicion, in order to learn about the
rules of engagement of Western forces.
Long-range reconnaissance is defined as recon in small groups behind the enemy lines, tens or hundreds of kilometers into hostile territory. This has much overlap with
guerrilla warfare. While almost every frontline military unit is sometimes assigned to do limited patrolling or surveillance of one kind or another, this kind of stealthy scouting far from friendly bases is a particularly dangerous mission.
Light cavalry often served this purpose in the past, and modern militaries keep specialized infantry units ready for similar roles, often verging on
special forces. When the recon team is unfamiliar with the terrain, recruitment of local guides can be very desirable for these kind of missions.
Network Reconnaissance
''Network reconnaissance'' is a process that is also defined as port scanning, network probes, network exploration, network enumeration or network service mapping. Network reconnaissance is increasingly being used to exploit various network standards and automated communication methods in order to determine what types of computers are present, along with additional information about those computers, such as the type and version of its operating system. This information can be analyzed for known or recently discovered vulnerabilities that can be exploited to gain access to secure networks and computers. Network reconnaissance is possibly one of the most widely used methods involving passive data analysis, though early generation techniques, such as TCP/IP passive fingerprinting, have accuracy issues that tended to make it ineffective. Today, numerous tools exist on the Internet that have been developed to either improve reconnaissance results or make reconnaissance easier.
These methods are also used by authorized administrators and professional vulnerability testing companies to help uncover or reveal potential vulnerabilities in order to better secure a network or group of computers. Typically, this process is called ''Penetration Testing'' or ''Pen Testing'' and is an increasingly important method for network administrators to use for validating security compliance to auditors.
See also
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Formation Reconnaissance Regiment
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Intelligence, Surveillance, Target Acquisition, and Reconnaissance
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Special Reconnaissance Regiment
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Særlig Støtte og Rekognoscering SSR - Special Support & Reconnaissance Coy (Danish)
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U.S. Marine Corps Force Reconnaissance
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U.S. Marine Corps Radio Reconnaissance
★ U.S. Army
Long Range Surveillance
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Joint Functional Component Command for Intelligence, Surveillance and Reconnaissance
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The South Alberta Light Horse
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The Queen's York Rangers (1st American Regiment) (RCAC)
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The Ontario Regiment (RCAC)
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United States Cavalry
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Surveillance aircraft
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Military Assistance Command, Vietnam Studies and Observations Group
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Rogers' Rangers
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2nd Cavalry Regiment (Reconnaissance)
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Traditional Apache scouts and
U.S. Army Indian Scouts
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Airborne pathfinders
External links
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Reconnaissance and Surveillance Operations—Canadian Land Forces manual about armoured reconnaissance (PDF)
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Israeli Special Forces Recon Units at isayeret.com
★ U.S. Centennial of Flight Commission: "Military Use of Balloons During the Napoleonic Era".
Accessed April 1, 2007.
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Advanced Network Reconnaissance with Nmap
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Nmap overview
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Network Reconnaissance defense techniques from ISSA
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XML Port Scanning Attacks
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Pen Testing VPNs article
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"A Tale of Two Airplanes" by Ltc. Kingdon R. Hawes