What Is an SSL VPN?

An SSL VPN is a security system providing encryption to network communications. SSL VPNs initially provided communication between any two endpoints, like the originally designed gateway-to-gateway architecture. But over time, many SSL VPN products have evolved to be more specific—now targeting secure remote access for client devices and excluding gateways and servers from this type of connectivity. The term “SSL VPN” stands for secure sockets layer (SSL) virtual private network (VPN). These programs protect unauthorized third parties from spying and eavesdropping on users’ communications, which otherwise might compromise sensitive data. Eavesdropping is among the greatest concerns for businesses, government agencies and journalists. SSL VPNs protect sensitive data from being accessed and guard against malicious man-in-the-middle attacks involving manipulating or altering information. An SSL VPN enables users to securely and efficiently access the company’s intranet resources from outside of the enterprise. An SSL VPN also allows users from any internet-enabled location to establish a remote access VPN connection with corporate resources. This greatly enhances productivity and availability while reducing the IT costs involved with software support and client equipment. Mobile employees can use this technology to work more efficiently on any device, whether a mobile phone or laptop computer.

SSL VPN Definition

The SSL and TLS protocols are the two protocols used to encrypt web traffic between a client browser and an SSL VPN device. The individual user of the VPN does not have to decide which protocol is being used for the VPN but can use both if necessary. Instead, the SSL VPN is automatically updated to use the newest and most-updated cryptographic protocol. Users don’t need to worry about updating the browser or operating system for new versions, as long as both are up-to-date. Whenever a browser or OS update occurs, any newer version of these protocols is downloaded automatically. The main function of SSL is to protect data that is transferred from one computer to another on a network between the VPN server and the client. SSL VPNs are popular among businesses since such services provide a way for employees to connect remotely to internal applications while away from offices. SSL VPNs are ideal for small businesses that need to protect sensitive business data, such as client lists and credit card information. The program also gives employees an easy way to connect and access the VPN at any time, even if users are in different locations around the country.

How Do SSL VPNs Work?

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SSL VPNs work by establishing a secure encrypted connection between the client and the network. This allows users to connect to internal resources remotely as if individuals were on the local network. The SSL VPN server acts like a proxy server responsible for authenticating users and encrypting traffic between the user’s computer or mobile device and the destination web server. The software also provides other functions, such as filtering traffic, caching content and presenting different versions of web content based on geographic location. In addition to SSL VPNs, there are also other VPNs, including IPsec or PPTP. These are generally used when the user wants to connect over a public network such as a hotel or airport wireless network or when using an untrusted network at places like a coffee shop or library.

SSL VPNs provide several features that enable the program to be an attractive remote access solution for business. Some of these features include access to applications and services from anywhere, multi-factor authentication, secure remote access with high levels of encryption and platform independence (with no need to install client software).

The security is enhanced through user authentication via a username and password or certificate-based authentication. The user’s identity is verified by accessing a specific resource on the network after entering the credentials. This is referred to as multi-factor authentication, as the user must have something in possession, such as a smartphone, to authenticate themselves. This provides an additional layer of security beyond just a username and password combination since the VPN requires more than something the user knows (the credentials) to gain access. In addition, if the user’s phone is lost or stolen, the account can be immediately locked down until the owner proves the identity by appearing at the office or calling the IT department.

What are the Types of SSL VPNs?

The two main types of SSL VPNs are given below.

  1. SSL Tunnel VPN
  2. SSL Portal VPN

1. SSL Tunnel VPN

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An SSL tunnel VPN allows users to securely access multiple network services, not just web-based ones. These services could be proprietary networks or software that’s exclusive for corporate use only and cannot be accessed directly via the internet. This VPN tunneling technology requires a browser with additional applications such as JavaScript or Flash to function. An organization must explain to employees what downloads or additional applications are needed to make the SSL tunnel VPN work properly.


One of the key functions of SSL tunnel VPNs is secure remote access. An SSL tunnel VPN allows users to securely access a corporate network from any location in the world. This feature makes the VPN a convenient option for remote workers and telecommuters who need to access corporate email platforms, internal websites, databases and applications.

SSL VPNs have several other functions as well, including secure mobile access. The VPN can be used on a laptop or mobile device such as an iPhone since the program does not require any additional software to run. The mobile user simply needs to have web access to use this function of an SSL tunnel VPN.

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Another advantage of SSL VPNs is secure VPN connections. An SSL tunnel VPN can be created between two separate intranets using two different internet service providers (ISPs). Additionally, SSL VPNs can be used to transfer files between company computers and workstations securely. This can be accomplished using the built-in FTP server or a third-party client such as Cyberduck, FileZilla or Transmit.

Users can configure SSL VPNs to allow access to a remote desktop, enabling users to connect from home and remotely log into the work computer or servers securely via an SSL-enabled web browser such as Google Chrome, Firefox, Internet Explorer or Safari. An SSL tunnel VPN can be used to connect to a computer from home and remotely administer the device, such as installing programs or files over a network connection. This is useful for IT professionals performing routine tasks on computers.

2. SSL Portal VPN

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With this type of SSL VPN, a user visits a website and enters credentials that initiate an encrypted connection. The SSL portal allows for up to one open-source SSL at the same time. Additionally, the user can access various private network services as defined by the organization using multiple IP addresses (each with a specific port number) simultaneously without interfering with each other’s use of internet traffic.

Users can enter the gateway or hardware on a network that enables data to flow from one network to another using any modern web browser by entering the username and password provided by VPN gateway services.


The functions of SSL portal VPNs include authentication and encryption: An SSL portal VPN provides login- and password-based authentication to access the network. The user’s browser must be configured to use the same encryption type as the SSL portal.

SSL portal VPNs provide access control so that users can access any private network provided by the organization and other private networks by establishing an encrypted connection with the gateway. These VPNs also enable seamless data transfer. The network can be accessed using various protocols such as HTTP, FTP, Telnet, SSH and others, depending on what is required for users’ personal needs.

The differences between SSL tunnel VPNs and SSL portal VPNs are that an SSL tunnel VPN is used to enable a user at one location to connect to another SSL tunnel VPN server at another location. In contrast, an SSL portal VPN provides a network or network segment that allows users to connect to an organization’s private network.

Another distinguishing factor is that SSL portal VPNs use a web browser, while SSL tunnel VPNs connect using a Secure Shell (SSH).

Why are SSL VPNs Important?

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With the ongoing rise in remote workers, SSL VPNs are critical to keeping the workforce connected with work applications and providing data security and privacy for companies. The programs provide a secure way for employees, contractors and partners from anywhere worldwide to gain access to the company’s most sensitive information from virtually any computer or device. Furthermore, SSL VPNs give IT full and granular control over data access. These VPNs are becoming more common in the workplace, and implementing the technology is a minimal learning curve.

SSL VPNs are a key component of an organization’s remote access strategy. However, organizations need to be aware of the risks and vulnerabilities associated with SSL VPNs. If not properly configured, SSL VPNs are vulnerable to man-in-the-middle attacks, which allow an attacker to intercept traffic between the client and the server. This can allow attackers to view sensitive information transmitted through SSL VPNs.

What are the Advantages of SSL VPNs?

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The primary advantage of SSL VPNs is that these VPNs are easy to deploy and use. In addition, the encrypted circuits created with TLS provide much more sophisticated outbound connection security than traditional VPN protocols. Another benefit of an SSL VPN is the program’s minimal administrative overhead. Unlike traditional VPN clients, this one is web-based, so users can use the software on any operating system an individual device is using. VPN clients typically require users to download the software for devices before using the program. An SSL VPN uses web-based applications that work on any operating system users’ devices are running. There are no extra steps required to configure the computer with SSL VPN because the software operates at the transport layer. This allows tunnels for accessing protected resources or applications that may be public and untunneled circuits for accessing public resources or applications. Finally, SSL VPN servers can restrict access to only specific applications, ensuring that users on a VPN connection cannot do anything malicious.

Are There Security Risks of SSL VPNs?

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While an SSL VPN provides a wide range of security benefits, the software also has some risks. The technology is especially vulnerable to spreading malware, such as spyware, viruses, worms and Trojan horse programs. If a remote user’s device isn’t running updated antivirus software, then malware from the local network of that user can spread to an organization’s network. Hacking a VPN is possible because of the “split tunneling” feature, which enables a user on an SSL to send both secured and unsecured traffic over the same connection. The split tunneling feature allows users to share network traffic with private networks while sending public network traffic through split tunneling. This can give attackers access to users’ web servers or other apps when hackers intercept the data in transit. Furthermore, suppose a computer on the network has an established SSL VPN connection to the company’s internal network and someone leaves the session open. In that case, the private corporate network will be exposed to anyone with access. Another potential danger when connecting to a VPN through an untrusted computer or network—like those of kiosks, for example—is that the user may be vulnerable to keyloggers. If this happens, attackers could intercept confidential information, such as passwords and other personal data, if the details are present in what the user types at the workstation.

What are the Best SSL VPN Products?

The best SSL VPN products are listed below.

  • Barracuda SSL VPN
  • Dell SonicWALL Secure Remote Access
  • Cisco IOS SSL VPN
  • Check Point Mobile Access Software Blade
  • OpenVPN Access Server
  • Juniper Networks SA Series SSL VPN

What is the Difference between a VPN and an SSL VPN?

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An SSL VPN uses a secure socket layer (SSL) technology to create a virtual private network (VPN). SSL is an encryption technology used to secure data traveling between a web browser and the website being visited. Most websites that require users to log in use SSL encryption. On the other hand, a reliable VPN definition states that the software is a program that makes the user’s online actions virtually untraceable by masking the associated IP address. This helps keep individuals anonymous on the internet and guards against threats such as government surveillance programs, third-party tracking, hacking, cyberattacks and data leaks.

In the case of a typical standard VPN, users will need to have software running on the machine for the VPN to work. However, an SSL VPN is designed to connect anywhere with any device through the web browser; this sometimes is called “SSL-Explorer.”

A VPN encrypts all traffic between users’ browsers and any site, while SSL is reserved for encrypting passwords, bank account numbers and credit card details.
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A VPN is a system that allows for logical isolation via cryptography. The program is “virtual” because the software doesn’t rely on physical connections to reach the VPN’s destination but rather through forms of encryption. On the other hand, SSL VPN technology takes the underlying transport medium and supplies a bonded, bidirectional medium. An SSL VPN provides confidentiality and ethics during transmission and possible authentication (generally server authentication).

An SSL VPN is a protocol for establishing secure connections between computers over a network (such as the internet). The software does not provide any privacy or confidentiality for the user. The program provides authentication of servers using certificates, but not of users. A VPN creates a secure tunnel between two endpoints that can be used for transmitting encrypted traffic over an insecure network. The tunneling protocols used by VPNs are also used in applications such as IPsec, SSTP and SSH.

The main similarity between an SSL VPN and a VPN is that these programs allow remote access to corporate networks. Both VPNs can support high-speed connections, and mobile users can use the program without installing any client software. Also, the programs protect data from being accessed by attackers for malicious reasons.

What are the Differences between an IPsec VPN and an SSL VPN?

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IPsec is a set of protocols used together to protect data sent over public networks. IPsec helps keep data sent over the internet secure by encrypting IP packets and authenticating the source. An SSL VPN works by establishing a secure channel between the client and the VPN server. Once the session is established, all data sent to or from the client is encrypted.

An IPsec VPN provides authentication of servers using certificates, but not of users. Conversely, an SSL VPN provides authentication for both servers and users. An IPsec VPN only encrypts the traffic between two endpoints, but an SSL VPN encrypts traffic between the client and server and between the server and destination server. This means that if one of the connections is compromised, only that single connection is exposed to the attacker, not all connections like in IPsec.

SSL VPNs have advantages over IPsec remote-access VPN connections. First, SSL VPNs don’t require additional software on client systems. Second, SSL VPNs can be set up using existing browsers and minimal configuration modification—making them more accessible to users.

SSL VPNs are easier to use than IPsec VPNs, requiring little configuration. This makes SSL VPNs ideal for deployment on the web.

IPsec VPN clients may break the principle of least privilege, exposing users’ private resources to potential attacks. An SSL VPN enables more precise access control by creating tunnels to specific applications and services. This feature allows organizations to provide different access rights for different users.

SSL VPNs are based on a similar model to IPsec in that both provide secure tunneling of data over an insecure network. Also, SSL VPNs are similar in that both offer a secure tunnel for data traffic.

Matthew Innes Matthew is an avid technology, security, and privacy enthusiast while also a fully qualified mechanical engineer. I love to see the crossover between these two fields. When he's not working or studying he can be found fishing, playing guitar, playing video games, or building something.