Resources > Glossary




Advanced Persistent Threat (APT)

An advanced persistent threat (APT) is an attack in which an unauthorized person gains access to a network and stays there undetected. APTs are “advanced” because they use malware that can bypass or evade many types of security protections. They are “persistent” because, once on the network, the malware is in regular communication with command-and-control (C&C) servers to which it can send stolen data or from which it can receive instructions.

Read how Zscaler protects against APTs.

Advanced Threat Protection (ATP)

Advanced Threat Protection (ATP) refers to a category of security solutions that defend against sophisticated malware or attacks targeting sensitive data. ATP detects and responds to new and sophisticated attacks that are designed to evade traditional security protections, such as antivirus, firewalls, and intrusion prevention systems.

Learn how the Zscaler platform protects against advanced threats, such as ransomware, polymorphic malware, and others.

AWS (Amazon Web Services)

AWS, a cloud services suite (including EC2, RDS, S3, SQS, and VPC), make up the Amazon cloud computing platform, which many companies are using to connect to private applications and workloads on the cloud.

Learn how Zscaler Private Access provides AWS customers with added security when they access AWS workloads — without the cost, complexity, or security risks of a VPN.



Network bandwidth is the measurement of a communications channel. Bandwidth varies and affects the speed and volume of data that can be transmitted over an internet connection.

Bandwidth Control

Bandwidth control is the practice of allocating available bandwidth to optimize the performance of mission-critical communications, such as Office 365, while reducing bandwidth allocation for lower-priority or recreational applications, such as YouTube.

Learn about Zscaler Bandwidth Control.

Behavioral Analysis

Behavioral analysis involves monitoring the behavior of a file in an isolated environment, such as a sandbox, to protect users from unknown (zero-day) threats. Through this monitoring, a file’s functions, and how it interacts with its environment, can be understood by IT security professionals. It also identifies whether a file will attempt to communicate with an attacker-controlled external server for command-and-control purposes or to download additional [malicious] files.

Learn about zero-day protection with Zscaler Cloud Sandbox.


A botnet is any number of internet-capable devices that, unknown to their owners, have been hijacked by malicious users and infected with code. This code may instruct the infected devices to spread the malware, or it may instruct them send repeated requests to a particular server, which results in a denial-of-service (DoS) attack.


See data breach.

Branch Transformation

Branch transformation is the enablement of traffic in the branch to be routed directly and securely to the internet, rather than being routed through MPLS links to the data center before it can go out to the internet. Branch transformation is a key element of IT transformation.


CASB (Cloud Application Security Broker)

CASB is software that acts as a liaison between cloud services customers and service providers. CASB provides visibility into what cloud services are being used and supports organizations with compliance, threat protection, and security for cloud services.

Learn about Cloud Application Visibility features in the Zscaler platform. Learn about Zscaler CASB partners.

CDN (Content Delivery Network)

A CDN is a system of servers distributed across a network. CDN servers copy and deliver web content closest to users based on their geographic locations, improving the delivery of content by speeding up page loads and optimizing overall network performance.

According to Cisco, 40 percent of internet traffic crosses CDNs. And, because that traffic is trusted, it tends to go uninspected by most organizations. Zscaler adds a layer of security and compliance between your existing infrastructure and the internet to protect against attacks hiding behind CDN-delivered traffic. Learn more.


The term cloud commonly refers to the internet, which supports the delivery of services to users on demand from a provider’s servers rather than their own. Cloud service delivery enables scalable, easy access to applications and services with fewer resources.

There is a distinction between public clouds and private clouds. Public clouds are multi-tenant environments in which organizations may consume applications, infrastructure, and services on a pay-per-use basis without the need to own the IT infrastructure. With public cloud services, organizations can add or remove users and services easily, thereby eliminating much of the management involved in the deployment of software and services. Private clouds, which may be housed onsite or in hosted environments, are single-tenant environments where the hardware, storage, and network are dedicated to a single organization. Private clouds are chosen by organizations that want the promise of greater control, privacy, and security, and they want to know exactly where their data resides.

Cloud Application

A cloud application is a software application that is delivered over the web as a service rather than from a data center or local machine. Examples of cloud applications include Microsoft Office 365, Google Apps, Salesforce, and Box.

Cloud Application Visibility

Cloud application visibility is the ability to see all the cloud applications in use throughout your organization, giving you the power to control and protect your data. Because Zscaler sits inline, it can see all traffic, coming and going, whether it’s sanctioned by IT or not.

Learn about Cloud Application Visibility features in the Zscaler platform.

Cloud Architecture

Cloud architecture refers to the components and subcomponents required for cloud computing. The front end is what the end user sees; it consists of interfaces and applications that are required to access the cloud computing platforms. The back end consists of all the infrastructure and resources required to provide the cloud computing service, which generally include servers, data storage, virtual machines, security mechanisms, services, and more.

The Zscaler security platform is built on a globally distributed, multi-tenant cloud architecture. It has been built from the ground up to deliver security and access controls on a massive scale. Its many patented technologies (100 as of January 2017) enable comprehensive security for users everywhere with ultrafast performance. Learn about the Zscaler cloud architecture.

Cloud Computing

Cloud computing is an internet-based, client-server approach to storing, managing, and processing data. Key features of cloud computing include on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. It enables the delivery of applications and business processes as services online, as opposed to resources like software and storage hardware that are “traditionally” housed onsite. The three main categories of cloud computer are Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).

Cloud Enablement

Cloud enablement is the process by which organizations create, deploy, and operate IT infrastructure, software, and resources that enable cloud computing.

Founded on the belief that cloud enablement is a business imperative, Zscaler helps to level the playing field by bringing sophisticated, cloud-delivered security to enterprises.

Cloud Firewall

A cloud firewall provides the network security, application control, and visibility features available in leading firewalls. But cloud firewalls have key advantages over hardware-based solutions. Cloud-based solutions can, for example, scan traffic in real time to provide global, up-to-date protection. Cloud firewalls can also scan encrypted traffic, whereas hardware solutions are extremely limited, and with the majority of internet traffic now encrypted, they leave a lot of traffic uninspected.

Zscaler Cloud Firewall brings next-gen firewall controls and advanced proxy-level security to all users in all locations. Because Zscaler is 100 percent in the cloud, there’s no hardware to buy, deploy, or manage. Learn more about Zscaler Cloud Firewall

Cloud Governance and Compliance

Cloud governance and compliance consists of a set of regulatory processes by which policies and procedures are created and followed to protect the security of cloud applications and data.

Cloud Sandbox

In general, a sandbox is a computing environment in which a program or file can be executed in isolation; if a file contains malicious code, the code can be detected before the file has the chance to infect a computer or network. Sandboxes have long been used by software developers to test new programming code and they have become a critical component of advanced threat protection.

Sandbox appliances generally sit in the data center and operate in TAP (Test Access Point) mode, which means that a file being tested is also sent on to its destination. If the sandbox detects malicious content, it sends an alert, but this can arrive too late. On the other hand, a cloud sandbox inspects internet traffic inline and executes programs in the cloud before it reaches its destination. It inspects files for all users everywhere, on the corporate network and off, there is no need to deploy sandboxes in dozens (or hundreds) of locations.

Learn more about Zscaler Cloud Sandbox.

Cloud Security

Cloud security consists of technologies designed to protect information, data, applications, and infrastructure, but unlike the stacks of appliances that sit at the gateway where they can scan inbound and outbound traffic, cloud security is delivered from the cloud.

Cloud security offers many advantages over hardware-based security, especially as users have become mobile and applications have moved to the cloud. It moves security from the network to the cloud, where it can scan all traffic, even if it’s encrypted, no matter where it is headed or where it originated. The cloud also reduces the cost and complexity of deploying and maintaining appliances.

Zscaler has designed and built the world’s largest cloud security platform with more than 100 data centers on five continents. Learn more about cloud security.

Cloud Security Alliance (CSA)

The Cloud Security Alliance (CSA) is dedicated to defining and raising awareness of best practices to help ensure a secure cloud computing environment. CSA works with industry experts, associations, governments, and its corporate and individual members to offer cloud security–specific research, education, certification, events, and products. CSA provides a forum through which diverse parties can work together to create and maintain a trusted cloud ecosystem. Zscaler CEO Jay Chaudhry is a founding member of CSA. Learn more at CSA.


The term cloud-washing refers to the deceitful practice of rebranding products and services with the term “cloud” to make them seem more relevant in today’s cloud-centric computing environment. Some vendors, for example, may host an existing product (hardware or software) in a virtualized environment and call it a cloud solution. But such an implementation has none of the characteristics of a true cloud solution, such as elasticity, multi-tenancy, or automated, continuous updates.



Data Breach

A data breach is an incident in which sensitive data, such as personally identifiable information (PII), trade secrets, or intellectual property, has potentially been viewed, stolen, or used by an unauthorized individual.

Data breaches in the corporate environment are common and may be the result of the theft or loss of a computing device, internal employees inadvertently introducing malware into the network, or external hackers directly targeting a company’s network. Because these incidents can damage a company’s reputation and are costly and time-consuming to mitigate, data breach prevention is a top priority in most IT environments.

DLP (Data Loss Prevention)

Data loss prevention (DLP) refers to systems with which organizations can prevent end users from sending sensitive information to unauthorized devices or recipients. DLP technology detects and blocks the movement of data based on policies set by the network administrator. Such policies may be based on dictionaries, which are algorithms designed to detect specific kinds of information in user traffic. They may also be defined by user or group, URL categories, location, and more.

Learn about the Zscaler Data Loss Prevention solution.

DDoS (Distributed Denial-of-Service)

A DDoS is an attack in which hundreds or thousands of computers or other internet-capable devices (a “botnet”) are hijacked to strike against a single system, network, or application. If an organization becomes compromised by a DDoS attack, its servers become overwhelmed by the barrage of “hits” from the botnet and its services become unavailable.

DoS (Denial of Service)

A DoS attack occurs when one compromised computer and internet connection inundates an entire system or resource. When an army of remotely controlled computers inundates an entire system, that’s called a Distributed Denial of Service (DDoS) attack. However, both types of attacks attempt to prevent internal employees and customers from accessing an organization’s web-based service by either flooding or crashing the servers.


Elasticity and scalability

The cloud is elastic in the sense that resource allocation can be increased or decreased on demand. Elasticity enables scalability, which means that the cloud can scale upward for peak demand and downward for lighter demand. Scalability also means that an application can scale whenever users are added or application requirements change.

A DDoS is an attack in which hundreds or thousands of computers or other internet-capable devices (a “botnet”) are hijacked to strike against a single system, network, or application. If an organization becomes compromised by a DDoS attack, its servers become overwhelmed by the barrage of “hits” from the botnet and its services become unavailable. >The Zscaler multi-tenant cloud architecture delivers elastic scale for our customers while maintaining security and data privacy. Learn more.


Encryption is the process of converting data into code to protect information from unauthorized access.

A majority of global internet traffic now uses Secure Sockets Layer (SSL) encryption, yet many organizations leave SSL inspection turned off, because it’s compute-intensive and severely impacts performance. The Zscaler cloud inspects every byte of traffic — SSL included — so we can catch hidden threats before they get into your network. Learn more.



Google Apps

Google Apps was launched in 2006 as a software-as-a-service (SaaS) offering. Today’s Google Apps includes an office productivity suite, email, and document sharing, as well as Gmail, Google Talk for instant messaging, Hangouts, Google Calendar, Google Docs, spreadsheets, presentations, and more.

To enable visibility into cloud-delivered applications, like Google Apps, Zscaler offers a Cloud Application Visibility and Control solution, which provides secure access and enables single sign‐on. Learn more.



HTTPS is an aggregate of HTTP and the Secure Sockets Layer (SSL)/Transport Layer Security (TLS) protocol, in which the authentication and encryption capabilities of SSL and TLS protect HTTP communications. HTTPS is widely used, accounting for roughly 80 percent of internet traffic according to Google. When a client accesses a website or a web application, HTTPS provides authentication for both the website and associated web server and encrypts data between the client and server.

An increasing number of malware authors are using SSL to hide threats, yet many organizations still allow SSL traffic to go uninspected. Learn about the Zscaler platform’s native SSL inspection.

Hybrid Cloud

A hybrid cloud is a networking environment that uses a combination of on-premises and public and private cloud platforms.


IoT (Internet of Things)

The IoT is the interconnection of a wide range of devices — thermostats, televisions, printers, security cameras, and more — that have IP addresses, enabling them to send and receive data.

While the IoT offers great potential for businesses to create new services and improve operational efficiencies, it offers a greater potential for security breaches. Zscaler provides comprehensive, cost-effective protection for all your internet-connected devices.

Read Zscaler research about the IoT threat.

Internet Security

Internet security encompasses browser security, the security of data entered through a web form, and overall authentication and protection of data sent via internet protocol.

Zscaler offers the world's first and only 100% cloud-delivered internet security platform — providing secure, policy-based access to the internet and private apps for every user, on any device, and in all locations. Learn more.




Malware, or malicious software, is any program or file that is designed to compromise a computer or network. Malware includes many varieties of computer viruses, worms, Trojan horses, spyware, and adware, and it has become both plentiful and sophisticated. Malware is coded to perform a range of functions, including stealing, encrypting, or deleting sensitive data; altering or hijacking core computing functions; and monitoring users' computer activity without their permission.

Zscaler inspects all traffic, including SSL, for unmatched protection against malware and other threats. Learn more.

Microsoft Azure

Microsoft Azure is a platform-as-a-service (PaaS) offering that enables developers to create and house cloud-based applications and services.

Microsoft Office 365

Microsoft Office 365 is the most widely used cloud-delivered enterprise application today. It has made the ubiquitous Microsoft Office suite of applications available as a subscription service. Because Office 365 was developed for cloud use, Microsoft recommends direct internet access for the best user experience, and distributed organizations with hub-and-spoke architectures are encouraged to enable local internet breakouts in their branch offices.

In addition, Microsoft Office 365 can often result in the need for infrastructure upgrades, as it dramatically increases the number of persistent connections that quickly exceed firewall capacities.

Zscaler makes Microsoft Office 365 deployment fast and easy, and enables secure local breakouts for remote offices, so users can quickly become productive. It requires no infrastructure changes — no hardware, no backhauling, and no impact on performance. Learn more.


Multi-tenancy is an architecture in which multiple systems, applications, or data from different enterprises are hosted on the same physical hardware. Multi-tenancy is a common feature of cloud-delivered services, as it allows clouds to share IT resources cost efficiently and securely.

Multi-tenancy is what enables the Zscaler cloud architecture to secure users anywhere they go because it allows policies to follow users. It also provides the scale needed to deliver multiple security services without latency. Perhaps most importantly, multi-tenancy is what fuels cloud intelligence, which means that if a threat is detected for any one of the 15 million users on the Zscaler cloud, protections are immediately propagated for all 15 million users. Learn more.


NGFW (Next-Generation Firewall)

NGFW is a hardware- or software-based network security system that detects and blocks sophisticated attacks by enforcing security policies at the application level, as well as at the port and protocol level.

The Zscaler Cloud Firewall provides NGFW protection for all users, in all locations, across all ports and protocols — without the need to deploy or maintain hardware or software. Learn more.




Ransomware is a type of malware (malicious software) that typically uses social engineering to trick a user into clicking a link or opening an attachment. Once opened, the malware encrypts files on the system or locks the computer and requires payment before access may be regained. Once a user has become infected, there is often little that can be done except pay the ransom, usually in BitCoins. Furthermore, if the infected user’s system is on a network, the malware can spread to other devices on the network.

To protect against ransomware, you need multi-layered security, with various tools working together to block malicious traffic and prevent attempts to contact command-and-control systems. The Zscaler Cloud Security Platform combines eight different security engines that allow you to quickly discover and block coordinated attacks. Learn more.




Salesforce, founded in 1999, is the first major cloud-delivered, pay-as-you-go platform. Salesforce upended the world of enterprise applications by delivering software as a service (SaaS) and betting on a pure-cloud future. The company has remained the leader in online customer relationship management (CRM) tools.

SD-WAN (Software-Defined Wide Area Network)

SD-WAN is software-defined networking (SDN) technology applied to WAN connections, which are used to connect enterprise networks — including branch offices and data centers — over large geographic distances.

Zscaler partners with leaders in SD-WAN to provide comprehensive security, visibility, control, and data protection for your users going directly to the internet on your network. Learn more.

Secure Web Gateway

A secure web gateway provides threat protection and policy enforcement for users accessing the web. It prevents users from accessing infected websites and prevents infected or otherwise unwanted traffic from entering an organization’s internal network. It is used by enterprises to protect their employees from accessing and being infected by malicious web traffic, websites, and viruses/malware.

The Secure Web Gateway is a critical component of the Zscaler Cloud Security Platform. The Zscaler Secure Web Gateway has been named a leader in the Gartner Magic Quadrant for secure web gateways for six consecutive years. Read more about Zscaler Web Security and Zscaler’s position in the Gartner Magic Quadrant.

SLA (Service-Level Agreement)

An SLA is a contractual agreement between a service provider and customer that defines the level of service, responsibilities, and priorities. An SLA also makes guarantees regarding availability, performance, and other service metrics.

Zscaler is ISO27001-certified and provides 99.999% availability guarantees, with additional SLAs on latency and security.

SSL (Security Sockets Layer)

SSL commonly refers to the two cryptographic protocols in computer network security — transport layer security (TLS) and its predecessor, security sockets layer (SSL). The purpose of SSL is to provide secure communications over a network, and SSL-encrypted data now accounts for more than 80 percent of all internet traffic, according to Google. Many malware authors now hide their malicious code inside SSL-encrypted traffic. Yet many organizations don’t scan SSL traffic, because it is compute intensive do to so, requiring considerable hardware upgrades.

Zscaler inspect every byte of traffic — including SSL-encrypted traffic — so we can block hidden threats before they get into your network. Learn more.

SSL Decryption, Encryption, and Inspection

SSL traffic accounts for about 80 percent of all internet traffic, making SSL decryption, encryption, and inspection a vital component of your security posture. ThreatLabZ researchers found that more than 54 percent of the malware discovered by Zscaler security engines was hidden behind SSL.

Zscaler inspects all traffic — including SSL-encrypted traffic — so we can block hidden threats before they get into your network. Learn more.


URL Filtering

URL filtering screens and blocks access or web content that is deemed inappropriate. URL filtering also protects against exposure to web-borne malware and viruses. URL filtering is a component of the Zscaler Secure Web Gateway. Learn more.



Zscaler Internet Access

Zscaler Internet Access is a 100% cloud-delivered replacement to the security stack of appliances in the outbound gateway. It provides multi-layered security for secure, policy-based access to the internet, for every user on any device in all locations across a distributed organization. Zscaler Internet Access includes Access Control services (Cloud Firewall, Bandwidth Control, URL Filtering, and DNS Filtering); Threat Prevention services (Cloud Sandbox, Advanced Protection, Antivirus, and DNS Security) and Data Protection services (Data Loss Prevention, Cloud Application Control, and File Type Controls). Learn more.

Zscaler Private Access

Zscaler Private Access provides policy-based, secure access to private, internal applications no matter where users connect or where the applications reside. With Zscaler Private Access, you can enable authorized users to access an application without allowing access to your network. And your private apps are never exposed to the internet. Learn more.

Zscaler Platform

Built on a global, multi-tenant architecture, the Zscaler platform is the world’s largest 100 percent cloud-delivered security platform with more than 100 data centers on five continents. The Zscaler platform is the foundation on which the Zscaler Internet Access and Zscaler Private Access services are built. Learn more about the platform.