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SDP vs. VPN vs. zero-trust networks: What's the difference?

For strong network security, many vendors say VPNs don't cut it anymore. Enter SDP and zero-trust models, which are similar yet offer stricter and innovative security capabilities.

To create a secure tunnel from one point to another or to make resources invisible to outside threats may seem like scenarios that require magic; in reality, they just need network security.

So begin the stories of VPNs, software-defined perimeter -- or SDP -- and zero-trust networks, three forms of corporate network security that present different approaches to security, with a shared goal of securing company resources. While VPNs have historically had a place in most network security plans, SDP and zero-trust networks are somewhat newer frameworks that aim to build off VPN capabilities and fill in the security gaps that VPNs miss. Still, VPNs have proven records of success in network security, while SDP and zero-trust models remain nascent.

Despite the differences between SDP vs. VPN vs. zero-trust networks, a shared goal for secure corporate networks ties the three technologies together, as does the increasing need for remote work support among organizations.

Defining SDP, VPN and zero trust

SDP. SDP is an overlay network -- or a network that sits atop another network connected with virtual or logical links -- that conceals network resources within a perimeter. Attackers and unauthorized users are unable to see or access the concealed resources, as the SDP acts as a cloud or an invisibility cloak to secure network resources.

SDPs use controllers to authenticate and connect authorized users to corporate network resources or applications through a secure gateway, based on identity policies, regardless of where the resources live in data centers, cloud services, etc. An organization may deploy SDP technology to reduce network-based attacks, which include denial-of-service or man-in-the-middle attacks.

VPN. VPN stands for virtual private network, and this technology encrypts tunnels between corporate networks and authorized end-user devices. With a VPN, remote employees can access network resources as if they were in an office directly connected to the corporate network. VPNs enable secure remote access for employees, regardless of whether they are in the office, at home or at a branch office location.

An organization may deploy VPN technology if it has a significant number of remote users or if it has more than one location for company resources to which employees require secure access. However, VPN shortcomings include a lack of support for diverse types of modern devices, such as IoT and mobile devices, that require network access.

Zero trust. Zero-trust networks trust no one. This means these models restrict every user's access to network resources, whether a user has accessed those same resources before or not. Any user or managed device that attempts to access resources within a zero-trust network must go through strict verification and authentication processes, even if that person or client is on premises in a company office.

Zero-trust models can expose potential gaps in traditional network security architectures, but these models can also introduce complexity in implementation, as the security framework can't have any gaps. Teams must also ensure the permissions and authorizations are constantly updated and accurate. Organizations that handle highly classified or sensitive data would benefit most from zero-trust network capabilities.

SDP vs. VPN vs. zero-trust comparison
Compare the similarities and differences between SDP vs. VPN vs. zero-trust networks.


Vendors have touted that VPNs are irrelevant and SDP is the future of corporate network security. While SDP technology does attempt to take after VPN capabilities and improve upon VPN shortcomings, VPNs are still widely used -- especially after the novel coronavirus pandemic forced all companies into remote work, if the businesses were able.

However, SDP may still be the next natural progression in network security technology in the next decade. Instead of SDP vs. VPN, organizations may also consider deploying SDP and VPN together. SDP technology could fill security gaps in VPN services, which include the potential for credential theft and increasing the size of the network's attack surface.

VPN vs. zero-trust networks

VPN and zero-trust capabilities exist on opposite sides of the network security spectrum; VPNs enable connectivity for authorized remote users and managed devices, while zero-trust networks restrict access to all users at all times. As cyberattackers grow more advanced with their attacks on networks, VPNs may not be enough to stop them -- especially if the attackers somehow gain authorized access. With zero-trust capabilities, attackers would still be restricted, regardless of whether they obtain authorized credentials.

However, it's possible for an organization to reap the benefits from both technologies. An organization may combine VPNs and zero-trust capabilities if it pairs SDP and VPN technology together, as SDPs can use zero-trust models to strengthen SDP security by delineating a clear network perimeter and creating secure zones within the network with microsegmentation.

SDP vs. zero-trust networks

Both SDPs and zero-trust networks are newer to network security than VPNs. This means these technologies have less proven success than VPNs do in the workplace, yet this also provides SDPs and zero-trust models with more room for innovation. As cyberattacks increase in volume and sophistication, enterprises can deploy SDP and zero-trust networks for more reliable and intuitive protection for modern networks.

SDP technology can use zero-trust capabilities to further protect network resources -- so, not only are users unable to see or access network resources hidden behind the perimeter, but those users will always go through strict authentication processes to access the resources.

One subset of zero trust is zero-trust network access (ZTNA), a Gartner-coined term for technology that creates a boundary, based on identity and context, around network applications or resources. Many experts use ZTNA and SDP interchangeably.

SDPs' and zero-trust networks' goals for stricter security will likely shape the future of network security for organizations.

Next Steps

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This was last published in June 2020

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