What Is SDP?

Internet-connected technologies (routers, servers, etc.) are hidden from hackers and external parties using an integrated security framework known as Software-Defined Perimeter (SDP). SDP works irrespective of the user’s device location (remote or onsite) or where the assets are housed (in the cloud or on-premises). The Cloud Security Alliance initially created the SDP approach.

The SDP approach aims to replace the hardware-based network perimeter (VPN or firewalls) with software. SDP is a software-based network perimeter with a wider range of applications and quicker deployment procedures. When an organization or a data center employs an SDP solution, it is like casting invisibility across its assets and servers, making them invisible to outsiders while only allowing infrastructure access to authorized users.

Traditional Network Security

An organization typically creates a corporate network security infrastructure to separate an internal network from the outside world. Firewalls and VPN stop threats from accessing the internal network and prevent hackers from investigating corporate network security protocols. Traditional security services successfully protected many systems by reducing the visibility of hackers and the attack vectors a malware might employ.

Shortfalls Of Traditional Network Security

The traditional network security model had flaws. The main reason is that each device becomes vulnerable since people handle many devices independently. The internal network layer and devices are secure if an IT admin manages device usage and establishes security measures for the network boundary and device protection. However, if a single person controls the device, they might be unable to defend it from assault sufficiently, resulting in network compromise.

Additionally, hackers utilize phishing attempts to access network data and specific resources. Email attacks are the most common way hackers launch a session attack. A phishing attack involves duping users into inputting login credentials on a website that the hacker utilizes to steal their data. The attacker can then obtain the user’s login credentials from the site’s database and use them to enter a system once the victim clicks a link in the email, visits a false site, and inputs the credentials.

Key Difference: SDP Vs. Traditional Network Security

Traditionally, organizations utilize firewalls and VPN to separate a few sensitive areas from the rest of the network perimeter for increased safety levels. However, those areas are typically broad. The principle of least privilege can be adapted logically to all situations using SDP’s considerably more precise micro division of resources. Considering asset distributions in cloud infrastructure, SDP controls access based on direct (one-to-one) connections rather than IPs. It indicates that SDP access is allowed to limited resources instead of an entire network. SDP technology replaces many of the conventional approaches of VPN or firewalls. However, it may be prudent to utilize firewalls or VPN for the internal division to minimize the malware reach.

What Does Software Defined Perimeter Do?

Software-defined perimeter solutions utilize a multi-step procedure to restrict resource access exclusively to authorized users:

Robust User Authentication

Software-defined perimeter (SDP) is an identity-driven access management framework. An SDP solution performs secure user identity authentication before granting access to network resources or data. It ensures user identity by supporting multi-factor authentication and other cutting-edge authentication techniques. Consequently, it reduces a company’s potential vulnerability to security breaches by ineffective credential safety measures—for example, credentials obtained through phishing attacks and other data infringements or weak passwords.

Device Authentication

Software-defined perimeter solution has an authentication method unconfined to the user access controls. Additionally, it can impose restrictions on the connecting device. Consequently, only company-owned devices or those currently compliant with the company’s security protocols may have broad access to resources or sensitive information.

Zero-Trust Enforcement

A zero-trust enforcement policy must replace the highly liberal access control guidelines that organizations previously utilized. A user is only authorized to access the specific resources to complete their tasks rather than having full resource access to the corporate network. The access level of each user is established and imposed through a role-based access control list generated according to their responsibilities in an organization.

Secure Access To Resources On An Internal Network

Software-defined perimeter (SDP) establishes a direct connection between users with access permission and the resources they utilize. This one-to-one connection is encrypted based on reliable threat intelligence and is subjected to comprehensive content analysis to detect and stop network vulnerabilities. This private and protected connection helps prevent hackers from intercepting or hijacking users’ access to confidential resources.

How Does SDP Work?

Software-defined perimeter providers are responsible for preventing unauthorized users from entering the corporate network boundary and accessing certain internet network areas. This is how SDP works:

  • Zero-trust security modelSingle Sign-on (SSO)vs
  • A black cloud approach
  • An access-after-authentication approach

Zero-Trust Security Model

The concept of zero trust holds that every individual, device, and network is hostile. They must establish their identity before being granted internet network access.

Suppose you move to an area where the security guard gives you a card key to access your house, gym, meeting area, etc. Every time you move in and out of the area, the guard allows you to enter the premises just by recognizing you. A traditional network security model works in this manner.

The guard permits it because you have the card key (access credentials). But if your twin uses the same card key, this guard will allow him inside like you. It is where a trust-based system falls short. A trust-based system permits accessibility if a similar device is used and verified one day and the next day. The person who steals the device might abuse that trust.

Contrarily, a zero-trust security system constantly inquires about individuals or entities attempting access. For simulating a real zero-trust system, the guard must require your biometric information for identity verification each time you enter the premises. Additionally, he will also authenticate the card key. Hence, internal network access is declined if the device is malicious or the user is a fraud.

SDPs Vs. Zero Trust Security

A software-defined perimeter (SDP) is entirely compliant with and resembles the zero-trust security method due to the kind of verifications it necessitates. Anyone attempting to access must pass authentication first. It also evaluates the device status to ensure that it does not pose any dangers and is secure. A connection won’t be permitted until the user’s credentials, and the device is secure.

If a user’s device, network, or user tries to connect, SDP acts as a locked front door, considering it a threat, and only allows the interface once it is authentic. Hence, SDPs relate to zero trust security.

Black Cloud Approach

Organizations can hide their network from attackers using black cloud infrastructure for network protection. With software-defined perimeter protection, the attacker cannot peek into the network. This eliminates the chance of creating attack strategies for the various network elements or protection measures.

As the name indicates, the black cloud renders the network invisible or “black.” It resembles a vault enclosed in a steel cube. To attempt theft, a hacker must breach the steel walls of the vault. Since the thief does not know internal security, thus they are clueless about preparing the technology or tools necessary to gain entry.

Various technologies are used for network security, like NGFWs, MFA, email security, web application security controls, etc. Hackers will be clueless about what they will find past the black cloud security.

Some software-defined perimeter providers offer services comparable to VPN (a virtual private network). Users who lack the necessary credentials are restricted. Contrarily, SDPs do not allow connected devices to share network connections.

Access-After-Authentication Approach

No one is permitted to access any network area without being authenticated when using an authentication first, access afterward strategy. Attackers are thus prevented from network visibility, its elements, applications, and internal systems. It allows additional access limitations utilizing added authentication methods like MFA once a user has entered.

SDP resembles a VPN (a virtual private network) because of the authentication-first-access-afterward strategy. But like a traditional VPN, SDP may be exposed if a user’s login information is hacked due to the absence of further security measures.

Since software-defined perimeter (SDP) does not automatically encrypt entire network traffic like a VPN, there is risk associated with depending on an authentication-first-access later strategy. Hence, a hacker getting access can eavesdrop on network communications. Therefore, the SDP solution necessitates further addition of security layers- for instance, WAFs and NGFWs.

SDP Architecture

SDP authenticates both devices and users before providing them with network access. Its architecture relies on controllers and hosts as its two main elements. Moreover, the SDP controller decides the SDP hosts’ communication method. SDP hosts initiate or accept the communication. The host initiating communication will connect with the controller. It determines which receiving host will be permitted to connect resources to the initiating host. A receiving host only accepts communication sent via an SDP controller.

Devices with which users attempt are called clients in SDP architecture. The client can connect to a particular network section in several ways. SDP gateway secures configuration between the client and the server. A client (a desktop application) sends a request to the receiving SDP host. Thus, the SDP gateway presents the client to the server and its resources after user identity and client authentication.

SDP Technologies And Cloud Security Alliance

Although independent SDP systems are available, an SDP solution is more of an architectural paradigm than a single protection solution because it integrates encryption, multi-factor authentication, network gateways, etc. The CSA outlined in its Software-Defined Perimeter (SDP) Architecture Guide that SDP architectures intend to incorporate at least five-layered security:

  • Device verification and authentication.
  • User authorization and authentication.
  • Encrypted two-way communications.
  • Flexible connection provisioning.
  • Service connections control with invisibility.

The SDP architecture distinguishes between the data and access control planes through network-aware gateways and firewalls, client-aware hardware, and user-aware software. The software-based SDP controller is the brain of the SDP tech infrastructure. It enables encrypted technology, authentication services, authorization services, and context-aware technologies like geolocation to centralize rules and manage the connection with SDP gateways and clients.

Benefits Of SDP Vs. Other Methods

The software-defined perimeter (SDP) solution is reliable, thorough, strong, and flexible that optimizes organizational network security for:

  • Operational freedom through automation and integration.
  • Enhanced and streamlined access controls.
  • Simplified policy management for administrators.
  • Minimized assault surfaces.
  • Enhanced end-user experience.

Other benefits include:

Multiple Layers Of Protection

SDP facilitates encrypted traffic tunnels for direct network connections and helps the IT department to mandate encryption tunnel usage before access takes place. Security tools (single sign-on, 2FA, etc.) can minimize a company’s attack surface.

Alleviate Hardware Restrictions

Hardware can never provide the personalized and limited access that SDP solution offers to individual users.

Real-time Remote Work Strength

Gateways are instantly established anywhere using SDP design and robust administration platform, enabling secure, streamlined, and minimal resources connectivity. Employees can securely and rapidly access resources regardless of their location.

SDP Application

SDP offers a wide range of applications and services, but businesses commonly use it for the following:

  • VPN alternative
  • Boosting M&A integration
  • Minimizing third-party risk
  • Multi-cloud access security

SDP Vs. Virtual Private Network (VPN)

SDP works to allow customized internal network entry regulations, whereas VPN is designed to give users limitless resource credentials. It permits IT visibility across the web, whereas VPN restricts it. When it comes to SDP vs VPN, the latter rarely automates policies.


Software-defined perimeter (SDP) creates a virtual perimeter surrounding corporate assets at the network layer rather than the application layer.

SDP also performs authentication of user access, identity, and devices. A Software-Defined Perimeter solution facilitates the IT staff to restrict resource access according to roles, every user, and other factors.

It enables organizations to accommodate several remote workers safely and comfortably utilizing several clouds.

Derik Belair

As President and CEO, Derik leads the vision, strategy and growth of Augmentt. Prior to founding Augmentt, Derik was the Vice President at SolarWinds, leading the digital marketing strategy for SolarWinds’ Cloud division. Derik has been working in the channel for over 20 years, starting his career as a channel sales rep at Corel Corp. and eventually becoming the first employee at N-able Technologies in April of 2000.
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