The incidents of security attacks are increasing and frequent accounts of serious security incidents are published by the news media. So, you might have come to a conclusion that network security is hopeless. But, luckily that is not the case since security issues can be addressed by different methods like overlapping controls for defense, reference monitors for access control and encryption for integrity and confidentiality.
The most prominent network security control measures include encrypted e-mail, intrusion detection systems and firewalls.
The most prominent network security control measures include encrypted e-mail, intrusion detection systems and firewalls.
Firewall
A firewall is a part of a computer system or network that is designed to block unauthorized access while permitting authorized communications. It is a device or set of devices that is configured to permit or deny network transmissions based upon a set of rules and other criteria.
Firewalls can be implemented in either hardware or software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which inspects each message and blocks those that do not meet the specified security criteria.
A firewall is a part of a computer system or network that is designed to block unauthorized access while permitting authorized communications. It is a device or set of devices that is configured to permit or deny network transmissions based upon a set of rules and other criteria.
Firewalls can be implemented in either hardware or software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which inspects each message and blocks those that do not meet the specified security criteria.
There are several types of firewall techniques:
1.) Packet filter: Packet filtering inspects each packet passing through the network and accepts or rejects it based on user-defined rules. Although difficult to configure, it is fairly effective and mostly transparent to its users. It is susceptible to IP spoofing.
2.) Application gateway: Applies security mechanisms to specific applications, such as FTP and Telnet servers. This is very effective, but can impose a performance degradation.
3.) Circuit-level gateway: Applies security mechanisms when a TCP or UDP connection is established. Once the connection has been made, packets can flow between the hosts without further checking.
4.) Proxy server: Intercepts all messages entering and leaving the network. The proxy server effectively hides the true network addresses.
Intrusion Detection System
An intrusion detection system (IDS) inspects all inbound and outbound network activity and identifies suspicious patterns that may indicate a network or system attack from someone attempting to break into or compromise a system.
An intrusion detection system (IDS) inspects all inbound and outbound network activity and identifies suspicious patterns that may indicate a network or system attack from someone attempting to break into or compromise a system.
There are several ways to categorize an IDS:
• misuse detection vs. anomaly detection: in misuse detection, the IDS analyzes the information it gathers and compares it to large databases of attack signatures. Essentially, the IDS looks for a specific attack that has already been documented. Like a virus detection system, misuse detection software is only as good as the database of attack signatures that it uses to compare packets against. In anomaly detection, the system administrator defines the baseline, or normal, state of the network??s traffic load, breakdown, protocol, and typical packet size. The anomaly detector monitors network segments to compare their state to the normal baseline and look for anomalies.
• network-based vs. host-based systems: in a network-based system, or NIDS, the individual packets flowing through a network are analyzed. The NIDS can detect malicious packets that are designed to be overlooked by a firewall??s simplistic filtering rules. In a host-based system, the IDS examines at the activity on each individual computer or host.
• passive system vs. reactive system: in a passive system, the IDS detects a potential security breach, logs the information and signals an alert. In a reactive system, the IDS responds to the suspicious activity by logging off a user or by reprogramming the firewall to block network traffic from the suspected malicious source.
Though they both relate to network security, an IDS differs from a firewall in that a firewall looks out for intrusions in order to stop them from happening. The firewall limits the access between networks in order to prevent intrusion and does not signal an attack from inside the network. An IDS evaluates a suspected intrusion once it has taken place and signals an alarm. An IDS also watches for attacks that originate from within a system.
Though they both relate to network security, an IDS differs from a firewall in that a firewall looks out for intrusions in order to stop them from happening. The firewall limits the access between networks in order to prevent intrusion and does not signal an attack from inside the network. An IDS evaluates a suspected intrusion once it has taken place and signals an alarm. An IDS also watches for attacks that originate from within a system.
Encrypted e-mail
Email encryption protects private, sensitive and valuable information communicated via email. Email encryption can be deployed using email encrypting software, secure email servers or secure webmail centers. E-mail encryption can rely on public-key cryptography, in which users can each publish a public key that others can use to encrypt messages to them; while keeping secret a private key they can use to decrypt such messages or to digitally encrypt and sign messages they send.
Email encryption protects private, sensitive and valuable information communicated via email. Email encryption can be deployed using email encrypting software, secure email servers or secure webmail centers. E-mail encryption can rely on public-key cryptography, in which users can each publish a public key that others can use to encrypt messages to them; while keeping secret a private key they can use to decrypt such messages or to digitally encrypt and sign messages they send.
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