Network security
In the field of networking, the specialist area of network security consists of the provisions made in an underlying computer network infrastructure, policies adopted by the network administrator to protect the network and the network-accessible resources from unauthorized access, and consistent and continuous monitoring and measurement of its effectiveness (or lack) combined together.
The First Step to Information Security
The terms Network Security and Information Security are often used interchangeably. Network Security is generally taken as providing protection at the boundaries of an organization by keeping out intruders (hackers). Information Security, however, explicitly focuses on protecting data resources from malware attack or simple mistakes by people within an organization by use of Data Loss Prevention (DLP) techniques. One of these techniques is to compartmentalize large networks with internal boundaries. Employees have to cross these boundaries and be authenticated when attempting to access protected information.
Network security concepts
Network security starts from authenticating the user, commonly with a username and a password. Since this requires just one thing besides the user name, i.e. the password which is something you 'know', this is sometimes termed one factor authentication. With two factor authentication something you 'have' is also used (e.g. a security token or 'dongle', an ATM card, or your mobile phone), or with three factor authentication something you 'are' is also used (e.g. a fingerprint or retinal scan).
Once authenticated, a firewall enforces access policies such as what services are allowed to be accessed by the network users.[1] Though effective to prevent unauthorized access, this component may fail to check potentially harmful content such as computer worms or Trojans being transmitted over the network. Anti-virus software or an intrusion prevention system (IPS)[2] help detect and inhibit the action of such malware. An anomaly-based intrusion detection system may also monitor the network and traffic for unexpected (i.e. suspicious) content or behaviour and other anomalies to protect resources, e.g. from denial of service attacks or an employee accessing files at strange times. Individual events occurring on the network may be logged for audit purposes and for later high level analysis.
Communication between two hosts using the network could be encrypted to maintain privacy.
Honeypots, essentially decoy network-accessible resources, could be deployed in a network as surveillance and early-warning tools. Techniques used by the attackers that attempt to compromise these decoy resources are studied during and after an attack to keep an eye on new exploitation techniques. Such analysis could be used to further tighten security of the actual network being protected by the honeypot.[3]
A useful summary of standard concepts and methods in network security is given by [4] in the form of an extensible ontology of network security attacks.
Once authenticated, a firewall enforces access policies such as what services are allowed to be accessed by the network users.[1] Though effective to prevent unauthorized access, this component may fail to check potentially harmful content such as computer worms or Trojans being transmitted over the network. Anti-virus software or an intrusion prevention system (IPS)[2] help detect and inhibit the action of such malware. An anomaly-based intrusion detection system may also monitor the network and traffic for unexpected (i.e. suspicious) content or behaviour and other anomalies to protect resources, e.g. from denial of service attacks or an employee accessing files at strange times. Individual events occurring on the network may be logged for audit purposes and for later high level analysis.
Communication between two hosts using the network could be encrypted to maintain privacy.
Honeypots, essentially decoy network-accessible resources, could be deployed in a network as surveillance and early-warning tools. Techniques used by the attackers that attempt to compromise these decoy resources are studied during and after an attack to keep an eye on new exploitation techniques. Such analysis could be used to further tighten security of the actual network being protected by the honeypot.[3]
A useful summary of standard concepts and methods in network security is given by [4] in the form of an extensible ontology of network security attacks.
Security management
Security Management for networks is different for all kinds of situations. A small home or an office would only require basic security while large businesses will require high maintenance and advanced software and hardware to prevent malicious attacks from hacking and spamming.
- Small homes
- Small homes
- Medium businesses
- Large businesses
- School
- Large Government
Top 100 Network Security Tools
After the tremendously successful 2000 and 2003 security tools surveys, Insecure.Org is delighted to release this 2006 survey. I (Fyodor) asked users from the nmap-hackers mailing list to share their favorite tools, and 3,243 people responded. This allowed me to expand the list to 100 tools, and even subdivide them into categories. Anyone in the security field would be well advised to go over the list and investigate tools they are unfamiliar with. I discovered several powerful new tools this way. I also point newbies to this site whenever they write me saying “I don't know where to start”.
Respondents were allowed to list open source or commercial tools on any platform. Commercial tools are noted as such in the list below. No votes for the Nmap Security Scanner were counted because the survey was taken on a Nmap mailing list. This audience also biases the list slightly toward “attack” hacking tools rather than defensive ones.
Each tool is described by one ore more attributes:
After the tremendously successful 2000 and 2003 security tools surveys, Insecure.Org is delighted to release this 2006 survey. I (Fyodor) asked users from the nmap-hackers mailing list to share their favorite tools, and 3,243 people responded. This allowed me to expand the list to 100 tools, and even subdivide them into categories. Anyone in the security field would be well advised to go over the list and investigate tools they are unfamiliar with. I discovered several powerful new tools this way. I also point newbies to this site whenever they write me saying “I don't know where to start”.
Respondents were allowed to list open source or commercial tools on any platform. Commercial tools are noted as such in the list below. No votes for the Nmap Security Scanner were counted because the survey was taken on a Nmap mailing list. This audience also biases the list slightly toward “attack” hacking tools rather than defensive ones.
Each tool is described by one ore more attributes:
Did not appear on the 2003 list 
Popularity ranking rose / fell the given number since the 2003 survey
Generally costs money. A free limited/demo/trial version may be available.
Works natively on Linux
Works natively on OpenBSD, FreeBSD, Solaris, and/or other UNIX variants
Works natively on Apple Mac OS X
Works natively on Microsoft Windows
Features a command-line interface 
Offers a GUI (point and click) interface 
Source code available for inspection.
