Network Terms "S"

Network Glossary and acronym's

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

SAM (Security Accounts Manager)

A database hive in the Registry that includes the directory database for a Windows NT computer.

Samba

Samba is an open source file sharing protocol that provides file and print services. Samba (based on SMB) allows non-Windows servers to communicate with Windows based applications and networks.

SAN (Storage Area Network)

A Storage Area Network (SAN) is an out-of-the-computer storage option for large systems. Instead of storage devices being connected inside of a server (known as Direct Attached Storage (DAS)), storage devices are instead connected to the network and then associated with one or more servers. SANs allow for greater capacity storage than is possible with DAS, and support high data transfer rates and clustering to provide high availability.

Scalability

The capacity of a single computer or an entire network to function well as you add or remove components (hardware or software).

Scatter Mode (Diffuse Mode)

One mode that an infrared device operates in is diffuse mode (also called scatter mode), which operates by broadcasting a large beam of light rather than a narrow beam. It does not require line-of-sight connections.

SCC (Single Copy Cluster)

Single Copy Cluster (SCC) uses shared storage in a failover cluster configuration which allows multiple servers to manage a single copy of storage groups. Because nothing in a single copy cluster is shared between the nodes, nodes have access to shared data, but cannot access it at the same time.

Schema

The schema is used to hold the blueprint for Active Directory in Exchange 2007. It defines all of the valid object types and attributes that can be associated with each object type on the Active Directory. If you try to create an object on an Active Directory domain controller that has not been defined within the schema, the domain controller will contact the schema master to make sure it has the latest copy of the schema. If the object is not defined, then the attempt to create the new object will fail.

Schema partition

An Active Directory partition that stores which types objects and attributes can be created in the Active Directory database.

Scope

A Microsoft term for a range of IP addresses that have been configured on a DHCP server awaiting assignment to a host.

Script

A file that lists actions to be executed when the script is run.

SCSI (Small Computer System Interface)

An interface used to connect microcomputers to physical devices (hard disks, scanners, and so on). The American National Standards Institute (ANSI) defines SCSI as a standard high-speed parallel interface.

SDR (Session Description Protocol)

Session Description Protocol (SDR) is an application tool that is commonly used to find multicast traffic by querying directories or listening to announcements. SDR encapsulates the following protocols:

Session Directory Protocol (SDP)
Session Announcement Protocol (SAP)

Sector sparing

A fault-tolerant feature that detects bad sectors of a hard disk, moves data from bad sectors to good sectors, and maps out bad sectors to prevent future use.

Secure File Transfer Protocol (SFTP)

SFTP is a file transfer protocol that uses Secure Shell (SSH) to secure data transfers. SSH ensures that SFTP transmissions use encrypted commands and data which prevent data from being transmitted over the network in clear text.

Secure Hypertext Transfer Protocol (SHTTP)

SHTTP (Secure Hypertext Transfer Protocol) is a proposed standard for security enhanced HTTP. It is used only for Web traffic. SHTTP is an alternative to SSL for Web traffic, but it does not employ SSL.

SHTTP should not be confused with HTTPS (Hypertext Transfer Protocol over Secure Socket Layer), which uses a URL of https://.

Secure Shell (SSH)

SSH (Secure Shell) is a secure and acceptable alternative to remote control systems such as Telnet. SSH allows for secure interactive control of remote systems. SSH uses RSA public key cryptography for both connection and authentication. SSH uses the IDEA algorithm for encryption by default, but is able to use Blowfish and DES.

SSH is comprised of slogin, ssh, and scp.

Secure Socket Layer over Hypertext Transfer Protocol (SHTTPS)

HTTPS is a secure form of HTTP that uses SSL as a sublayer for security.

Secure Sockets Layer (SSL)

A protocol that provides encryption for communication between the Internet servers and browser clients. It uses public/private key cryptography and digital certificates to verify users' identities.

Security Accounts Manager (SAM)

A database hive in the Registry that includes the directory database for a Windows NT computer.

Security Analysis and Configuration Snap-In

A Microsoft Management Console (MMC) snap-in that lets you compare a computer's current security settings with an existing security template. You can also save security settings as a new security templates.

Security Identifier (SID)

A unique ID used to identify everything in the domain.

Security log

A text file containing records of events you have chosen to audit. For example, if you chose to monitor unsuccessful attempts to log on to your system, you would look at the security log to find the results of that audit.

Security Subsystem

The Windows subsystem that handles the process of logging on to a domain. It works with the Security Accounts Manager to validate the given user name and password, generates an access token, and returns it to the user.

Security template

A group of security-related settings stored in a file. Security templates can be imported into a Group Policy Object (GPO).

Seed metric

The seed metric is the default metric or cost for a redistributed route.

In OSPF, the seed metric is based on the interface's bandwidth.
In IS-IS, the default seed metric is 10.
In EIGRP and IGRP, the default seed metric is based on the interface bandwidth and delay.
In RIP, the seed metric starts with a hop count of 0 and increases from router to router in increments.

Segmentation

Segmentation is a Transport layer process of breaking large packets of information from higher layers into smaller packets called segments. Segmentation is necessary to enable the data to meet network size and format restrictions. The other function of segmentation happens when the receiving Transport layer uses packet sequence numbers to reassemble segments into the original message.

Separator page file

A page you can print between each print job sent to a printer. Also called a banner.

Serial Line Internet Protocol (SLIP)

An industry-standard protocol developed in 1984 to support TCP/IP over low-speed serial interfaces. Windows 2000 supports SLIP client functionality, but not server functionality. Also, Windows NT RAS Servers do not accept SLIP client connections.

Serial port

A serial port transmits and receives data one bit at a time. The modem and mouse connect to a computer through a serial port.

Server

A computer that runs a server program (or the server program itself) providing services to users and other computer programs on a network.

Server Management Services (SMS)

A Microsoft management utility that provides management for Windows NT servers.

Server Message Block (SMB)

The file-sharing protocol used on all MS Net products. A workstation communicates with an SMB server process at the remote host.

Server object

An Active Directory object that represents the physical location of a server (usually a domain controller) on a Windows 2000 network.

Server Operators

A built-in local group on domain controllers only. Server Operators share disk resources and can back up and restore the server.

Server-only backup

A backup technique that backs up the data stored on the server. This requires fewer backup devices and storage media, but requires all users to store critical files on the server.

Service

A computing process that performs a specific task in the system. It may also provide a programming interface for other processes.

Service packs

Updates to the Windows 2000 operating system that Microsoft periodically issues. They include bug fixes and other improvements and are available at no cost from the Microsoft web site.

Service provider

The organization that provides a WAN service to an individual or company. A service provider might be the same organization that owns the WAN, or it might be a separate organization that purchases network access from a WAN carrier and then resells network access to the general public.

Service Set Identification (SSID)

A type of wireless security feature used to group several wireless devices and access points as part of the same network and to distinguish these devices from other adjacent wireless networks. The SSID is also commonly referred to as the network name. Most WAPs come with a default SSID, which you should change as part of your security implementation. Even after you change the SSID, it is still only a minimal security feature. There are two type of SSIDs:

BSSID (Basic Service Set Identification) is used by an ad-hoc wireless network with no access points.
ESSID (Extended Service Set Identification), or ESS Identifier, is used in an infrastructure wireless network that has access points.

Session

A session refers to a communication between two end points (usually between client and service) that occur during a single connection. The session begins when the connection is established at both ends and terminates when the connection is ended.

Session Description Protocol (SDR)

Session Directory Protocol (SDP)
Session Announcement Protocol (SAP)

Session Layer

Layer 5 of the OSI reference model. This layer establishes, manages, and terminates sessions between applications. It also manages data exchange between presentation layer entities. It corresponds to the data flow control layer of the SNA model. See also application layer, data link layer, network layer, physical layer, presentation layer, and transport layer.

SFTP (Secure File Transfer Protocol)

Share name

The name of a folder that many users will access on a network. Use intuitive share names so that your users can easily identify resources.

Share permissions

Security to control how users access a shared folder.

Shared folder

A folder that is used by a group of people on the network. Shared folders give access to users of applications, data, and home folders.

Shared printer

A printer that is connected to the network so many users can access it.

Shared-file messaging system

A messaging system based on a server/client relationship in which the client takes the active role in delivering and processing messages. The server is simply a repository of shared files. Microsoft Mail 3.x and Lotus cc:Mail are shared-file messaging systems.

Shielded Twisted Pair (STP)

Twisted pair cables support a wide variety of fast, modern network standards. Twisted pair cabling is composed of two wires that carry the data signals. PVC plastic insulation surrounds each wire. Two wires are twisted to reduce the effects of electromagnetic interference and crosstalk. Because the wires are twisted, EMI should affect both wires equally and can be cancelled out. Multiple wire pairs are bundled together in an outer sheath. Twisted pair cable can be classified according to the makeup of the outer sheath. Shielded Twisted Pair (STP) has a grounded outer copper shield around the bundle of twisted pairs or around each pair. This provides added protection against EMI.

Shiva Password Authentication Protocol (SPAP)

The SPAP protocol is a more secure version of PAP. SPAP uses an encrypted password for authentication. Password encryption is easily reversible. SPAP is required to be connected to a Shiva LAN Rover (proprietary).

SHTTP (Secure Hypertext Transfer Protocol)

SHTTP should not be confused with HTTPS (Hypertext Transfer Protocol over Secure Socket Layer), which uses a URL of https://.

SHTTPS (Secure Socket Layer over Hypertext Transfer Protocol)

HTTPS is a secure form of HTTP that uses SSL as a sublayer for security.

Shutdown script

A script that executes when a computer shuts down.

SID (Security Identifier)

A unique ID used to identify everything in the domain.

Simple Mail Transfer Protocol (SMTP)

The Internet standard protocol for transferring e-mail messages between hosts. SMTP assumes that both host and client are constantly connected, but you can use both permanent and dial-up connections to an SMTP host.

Simple Network Management Protocol (SNMP)

A simple protocol for managing TCP/IP networks. It is used to report the status of a host on a Windows TCP/IP network. Network equipment vendors developed SNMP to let management software monitor network components. Using SNMP, programs called agents are loaded on to each network component. The agents monitor network traffic and other network components and compile the information in a management information base (MIB). Windows 2000 uses SNMP to check the status of another computer on a TCP/IP network.

Simple Password Authentication Protocol

Simple Password Authentication Protocol is used to authenticate a user to a network access server. Simple password authentication protocol:

Allows a password (key) to be configured per area. Routers in the same area that want to participate in the routing domain will have to be configured with the same key.
Is commonly used by internet service providers.
Is a Point to Point Protocol.
Is supported by almost all network operating system remote servers.

Simplex (Duplex)

Simplex and duplex are methods of communication transmission. Simplex is the one-way transmission of a signal across a medium. Duplex is the two-way transmission of a signals across a medium. There are two types of duplex transmission; half-duplex and full-duplex. Half-duplex allows transmission of signals, one party at a time. Full-duplex allows transmission and reception of signals to occur concurrently.

Single Copy Cluster (SCC)

Single domain model

A Windows NT domain model in which all users and groups reside in one domain, with a single PDC and one or more BDCs. This model does not use trust relationships because there is only a single domain. Typically used for centralized administration of accounts and resources.

Single master domain model

A Windows NT domain model consisting of at least two domains. Each of the domains has its own domain controller, but all account information is kept on the master domain's controllers. The single master domain model is used when a company has divisions and departments where each entity has its own resource management, but there is still centralized account management.

Single-master replication model

A replication model in which updates can only be made to one domain controller (master). The master then replicates its updates to other domain controllers. Windows NT 4.0 used this replication model.

Site

A TCP/IP subnet or group of well connected subnets. If subnets are well connected the connection is very reliable and fast. Sites make it easier to configure Active Directory access and replication to best utilize the physical network.

In Windows 2000, a site is a physical unit that defines replication for Active Directory informatioon. Each site includes one or more servers within an organization. To be in the same site, servers need permanent, high-speed LAN or WAN connections to each other.

Site link bridge object

An Active Directory object that models which site links should be bridged (in other words, over which site links IP packets can be routed).

Site link object

An Active Directory object that represents a non-permanent or low-bandwidth link between multiple sites.

Site object

An Active Directory object that represents a group of permanent, high-bandwidth TCP/IP subnets.

Sliding windows

A sliding window is used to buffer data transmission between two hosts. Each TCP/IP host maintains two sliding windows: one for receiving and the other for transmitting data. The size of the window is the amount of data that can be buffered on a computer.

SLIP (Serial Line Internet Protocol)

Small Computer System Interface (SCSI)

SMB (Server Message Block)

The file-sharing protocol used on all MS Net products. A workstation communicates with an SMB server process at the remote host.

Smooth Round Trip Time (SRTT)

The Smooth Round Trip Time (SRTT) is the average time in milliseconds between the transmission of a packet to a neighbor and the receipt of an acknowledgement.

SMP (Symmetric Multiprocessing)

Using multiple processors that share the same operating system and memory to process programs more quickly.

SMS (Server Management Services)

A Microsoft management utility that provides management for Windows NT servers.

SMTP (Simple Mail Transfer Protocol)

SMTP service domains

A method of organizing e-mail messages. The default domain and local domains include e-mail addresses hosted on the local Microsoft Internet Information Server computer. Remote domains include e-mail addresses hosted on other SMTP computers.

SNA (Systems Network Architecture)

A protocol suite that is a complete networking system, including proprietary hardware. SNA enables communication between IBM mainframes and terminals. It also interfaces with IBM Token Ring local area networks.

Snap-in

A tool used through Microsoft Management Console (MMC). Snap-ins can be stand-alone (can be added to MMC by itself) or extension (can be added to MMC only to extend the function some other snap-in).

SNMP (Simple Network Management Protocol)

SNMP agent

An SNMP agent performs get, get-next, and set operations requested by a management system. An agent can be any computer running the SNMP agent software, usually a server or router.

SNMP trap

An SNMP agent performs a trap, which is an alert that is sent to management systems for some event that has occurred with that device. This event could be excess traffic, password violations, or a hardware failure.

Snmputil

A utility that verifies whether the SNMP Service has been correctly configured to communicate with SNMP management stations. For example, you can use the utility to determine the number of DHCP Server addresses leased by a DHCP server in the Public Community.

SNPA (Subnetwork Point of Attachment)

A Subnetwork Point of Attachment (SNPA) is a point in a network that provides subnetwork services; comparable to the layer 2 address corresponding to the NET or NSAP address. The SNPA is assigned by using one of the following:

The MAC address on a LAN interface.
The virtual circuit ID from X.25 or ATM connections.
The Data-Link Connection Identifier (DLCI) from Frame Relay connections.

Social engineering

Social engineering is an attack where someone claims to be someone other than who they are. Attackers can assume any role within your organization or of anyone outside of your organization. Their goal is to get you to disclose confidential or sensitive information verbally or to perform some action on the computer system that would grant the attacker access, such as changing a password based on a verbal request over the phone by someone claiming to be an offsite manager. Some common social engineering attacks are:

Dumpster diving -- Going through someone's trash to find private information.
Keyboard surfing -- Observing sensitive information by looking over one's shoulder.
Piggybacking -- Gaining access into a secure facility by slipping in as an authorized visitor enters.
Phishing -- Sending legitimate-looking e-mails designed to trick the recipient into divulging private information (often identity theft related activities).

The primary countermeasure to social engineering is awareness. If users are unaware of the necessity for security in your organization and they are not properly trained to support and provide security, they are vulnerable to numerous social engineering exploits. Awareness training focused on preventing social engineering should include methods to authenticate personnel over the phone, assigning classification levels to information and activities, and educating your personnel on what information should not be distributed over the phone.

Sockets

A socket is much like a file handle and functions as an endpoint for network communication. Each application creates a socket by specifying the IP address of the host, the type of service (connection oriented, connectionless), and the port that the application is using.

Software distribution point

A network share that stores software installation programs and/or data and from which software can be installed.

Software modification file

A file with the .MST extension that can be applied to a Windows Installer package (.MSI file) to customize it. Also called a transform file (.MST).

Software package

A Windows Installer package (.MSI file) or ZAP file that is distributed to network users using an Active Directory-based Group Policy Object (GPO).

Source compatible

An application that can run only on the hardware platform for which it was originally compiled.

Source replication partner

A replication partner that sends updates to a target replication partner.

Spanned volume

A volume on a dynamic disk that spans multiple physical drives. Spanned volumes are not fault tolerant and nor can you mirror spanned volume. In Windows NT 4.0, a spanned volume was called a volume set.

SPAP (Shiva Password Authentication Protocol)

Spider

A program that explores links inside and outside a Web site. Also called a robot.

Split horizon

Using the split horizon method (also called best information), routers keep track of where the information about a route came from. Routers do not report route information to the routers on that path. In other words, routers do not report information back to the router from which their information originated.

Split horizon with poison reverse

Using the split horizon with poison reverse method (also called poison reverse or route poisoning), routers continue to send information about routes back to the next hop router, but advertise the path as unreachable. If the next hop router notices that the route is still reachable, it ignores the information. If, however, the path timeout has been reached, the route is immediately set to unreachable (16 hops for RIP).

SQL (Structured Query Language)

A query and programming language for databases, widely used with relational database systems. SQL translates what the user sees on the display to commands that the server can understand. IBM originally developed SQL as an English-like query language for entering, editing, and retrieving data in mainframes. There is now an ANSI-standard SQL definition.

SRTT (Smooth Round Trip Time)

The Smooth Round Trip Time (SRTT) is the average time in milliseconds between the transmission of a packet to a neighbor and the receipt of an acknowledgement.

SSH (Secure Shell)

SSH is comprised of slogin, ssh, and scp.

SSID (Service Set Identification)

BSSID (Basic Service Set Identification) is used by an ad-hoc wireless network with no access points.
ESSID (Extended Service Set Identification), or ESS Identifier, is used in an infrastructure wireless network that has access points.

SSL (Secure Sockets Layer)

A protocol that provides encryption for communication between the Internet servers and browser clients. It uses public/private key cryptography and digital certificates to verify users' identities.

Standard area

A standard area allows any type of route information to enter or leave the area.

Standard primary zone

An authoritative DNS server for a zone that contains a read-write copy of the zone file and can be updated directly. The updated zone information can then be replicated to secondary zones.

Standard secondary zone

An DNS server that contains a read-only copy of the zone file. The zone information is updated by replication from other servers. Its zone file can then be replicated to other secondary zones.

Standby server

A standby server is a Windows 2000 server that you have configured as an emergency backup server. It has Windows 2000 and all necessary components installed, but has not joined a domain.

Star

Star is a network topology that uses a hub (or switch) to concentrate all network connections to a single physical location. Today it is the most popular type of topology for a LAN.

Startup script

A script that executes when a computer starts up.

Static mapping

A router that is configured to communicate only with networks to which it has a configured interface. To route IP packets to other networks, each static router must be configured with either an entry in each router's routing for each network in the internetwork or a default gateway address of another router's local interface.

Static route

A static route is a route that is manually configured to a remote destination. They can be used to reduce overall traffic because they do not require information to be generated. Static routes are most commonly used to:

Define specific routes to use when routing information must be exchanged between two autonomous systems. This eliminates the need for entire routing tables to be exchanged.
Define routes to destinations over a WAN link. This eliminates the need for a dynamic routing protocol.

Static routing

Static routing is an addressing method in which IP configuration information must be built and updated manually on each host by an administrator.

Storage Area Network (SAN)

STP (Shielded Twisted Pair)

Stripe sets

A method of saving data by writing it in stripes across several different hard disks at once.

Striped volume

A striped volume breaks data into units and stores the units across a series of disks (as opposed to a spanned volume that fills the first area with data, then the second area, and so on). Striped volumes:

Do not provide fault tolerance. A failure of one disk in the set means all data is lost.
Provide an increase in performance.
Use two or more disks.
Have no overhead--all disk space is available for storing data.

Striping

Striping is a data protection method. Striping divides data into units and stores the units across a series of disks. Distributing the data removes the threat of losing all of the data in event of a single disk failure.

Structured Query Language (SQL)

Stub area

A stub area does not allow ASBR routes, so routes that are external to the OSPF routing process are not transmitted.

Stub routing

Stub routing is a topology in which the remote router forwards all traffic that is not local to a hub router.

Subkeys

A key inside another key in the Registry. Subkeys can contain more subkeys or values.

Subnet

A physical segment in a TCP/IP environment that uses IP addresses created from a single network ID. The subnet is created by partitioning the bits in the host ID into two parts. The first part is used to identify the segment as a unique network, and the other part is used to identify the hosts. Companies typically used subnetting because they exceeded the maximum number of hosts per segment with their IP address.

Subnet mask

The concept of blocking out a portion of the IP address so that TCP/IP can determine the network ID from the host ID. TCP/IP hosts use the subnet mask to determine whether the destination host is located on a local or remote network. Typically the subnet mask is 255.255.255.0.

Subnet object

An Active Directory object that represents a TCP/IP subnet.

Subnetting

Subnetting is the division of a network address into multiple smaller subnets. For example, this allows a single Class B or Class C addresses to be divided and used by multiple organizations.

Subnetwork Point of Attachment (SNPA)

The MAC address on a LAN interface.
The virtual circuit ID from X.25 or ATM connections.
The Data-Link Connection Identifier (DLCI) from Frame Relay connections.

Subtree

The folders and subfolders contained inside the export directory you use for directory replication.

Successor route

A successor route is the best route to a destination.

Supernetting

Supernetting, combining multiple network addresses into a single larger subnet. For example, this allows multiple Class C addresses to be combined into a single network.

Superscope

In Windows 2000 Server, a grouping of multiple DHCP scopes into a single unit. A superscope makes it possible to have multiple logical subnets on a single physical subnet. The individual scopes are called member scopes or child scopes.

SVC (Switched Virtual Circuit)

An on-demand virtual circuit that is maintained for the length of a conversation. When the conversation ends, the connection is released.

Switch

A network device that works at the data link layer and allows each device to have higher bandwidth on the network. A switch can offer speeds of 10 to 100 megabits to the desktop.

Switched 56

A system of Digital Data Service (DDS) lines that are on-demand (dial-up) instead of leased and transfer data at a rate of 56 Kbps.

Switched Virtual Circuit (SVC)

An on-demand virtual circuit that is maintained for the length of a conversation. When the conversation ends, the connection is released.

Switches

Codes you can use at the command prompt when starting an application or installation program to customize the way the program runs. Also called command line switches.

Symmetric Multiprocessing (SMP)

Using multiple processors that share the same operating system and memory to process programs more quickly.

Synchronization

The mechanism by which domain controllers share directory changes and ensure that their information is accurate.

SYSCON

A GSNW or CSNW utility that lets you set up user accounts, define policies, and grant user permissions on a NetWare network from a Windows NT computer.

Sysdiff.exe

An executable file you can use during an unattended installation of Windows NT if you need to install an application that does not support scripted installations.

System groups

Built-in groups that organize users for system use. You do not assign users to a system group; these groups are automatically updated by Windows 2000. Users become members of system groups by default or as a result of network activity. The the four main system groups are Everyone, Creator Owner, Network, and Interactive.

System hive

A hive in the Registry which includes information about the devices and services installed on the computer.

System log

A text file containing the events that Windows 2000 components log, such as driver failures. You can use the Event Viewer to display the system log.

System Monitor

A Windows 2000 tool that is used to monitor real-time and historical system performance, trends, bottlenecks, and the effects of system configuration changes.

System partition

The partition on the hard disk containing the boot files and hardware-specific files for the operating system.

System policy

A set of registry settings that controls what users can see and do on their Windows NT computers. System policies are used to control and manage desktop computers. You can use system policies to provide all users or computers with a uniform system policy, or customize settings for specific users, groups, and computers. Windows 2000 computers use Group Policy instead.

System Policy Editor

Poledit.exe. A graphical front-end to the registry included with Windows NT Server that allows you to make registry changes without using the registry editor.

System policy files

The files containing the rules governing how a Windows NT client computer will display the desktop, use Control Panel options, access the network, and so on. Ntconfig.pol is a default system policy file. Windows 2000 computer use Group Policy Objects (GPOs) instead.

System state data

System state data includes all the Windows 2000 system components and distributed services that Active Directory depends on.

Systemroot

The directory in which you installed the Windows 2000 operating system files.

Systems Network Architecture (SNA)