TightVNC

Another remote desktop application is TightVNC (Figure 2), which likewise works with VNC and thus with RFB as a protocol. The software is licensed under the GPL, allowing users to work with it freely both in personal and commercial environments. TightVNC is written in C, C++, and Java, and it is available for the Linux and Windows platforms. Mixed operation of both systems is also possible; the vendor also offers a Java viewer, as well as an Android viewer with Remote Ripple [10].

Figure 2: TightVNC over a SSH tunnel with PuTTY.

Since the Java viewer has been around, there is no longer any separate Linux version of the client. This existed only up to TightVNC 1.3.10. The software can also be installed via the package manager of most distributions.

TightVNC is compatible with the client or server components of other VNC implementations. The tool focuses on compression, specifically using JPEG and zlib. This is also how it copes with low bandwidths. Users can watch movies and play DirectX games, even with a reduced image refresh rate on broadband connections. TightVNC encrypts passwords individually; complete encryption is on the agenda. To heighten security, the developers recommend tunneling connections over SSH.

With TightVNC, users control the desktops of remote machines. In version 2.0, the program introduced autoscaling, adjusting the size of the display in the viewer to that of the remote machine, regardless of the client's resolution. The admin can reduce the system resources required for the Windows platform (Figure 3) by installing the DF Mirage Driver Hooks [11] on the server side.

Figure 3: On Windows, access to the VNC server often requires modifications to the firewall. When using TightVNC, the admin should also install additional software to free up resources.

Additionally, TightVNC has spawned various offshoots, such as RemoteVNC, TightVNC Portable, TurboVNC, and TigerVNC [12]. The latter of these departed from its mothership in 2009 and is Fedora's standard VNC application.

Unlike TightVNC, TigerVNC is equipped with extensions that let users authenticate and encrypt with transport layer security (TLS). Its software focuses mainly on 3D display and video applications.

Lookalikes

TeamViewer and AnyDesk have much in common but also exhibit clear differences. Both applications are commercially designed, use proprietary protocols, and offer their own free versions for personal use. Both offer plenty of comfort – thanks to user-friendly GUIs (Figure 4) – penetrate firewalls without manual intervention from the admin, and require hardly any configuration. The admin manages the access privileges via black- and whitelists.

Figure 4: TeamViewer offers a range of options on the graphical interface's navigation bar.

TeamViewer

TeamViewer (Figure 5) is a contender both for personal and business use. The remote maintenance software offers screen sharing, video conferencing, file transfers, chats, and VPN. It is available for Windows, OS X, and Chrome OS, as well as for RPM-based and Debian-based Linux distributions. Unlike AnyDesk, it does not run natively on Linux, but requires a Wine environment. Only a 32-bit version is available for Linux, meaning a multi-architecture system is necessary. TeamViewer supports Android, iOS, and Blackberry with apps in both directions, and there is a viewer for Windows Phone.

Figure 5: With TeamViewer, a Linux device can even comfortably access a Windows one.

TeamViewer connects machines over secured data channels and initiates the encryption via a 2048-bit RSA public private-key exchange. After this, the software uses symmetrical 256-bit AES end-to-end encryption. This process is considered secure by current standards. Additionally, Verisign code-signs the software, with the intent of guaranteeing that only legitimate variants are in circulation. TeamViewer also offers commercial customers two-factor authentication.

For their payment model, the company relies on the sale of licenses. The customer pays a one-time fee and can then use the software without restriction. The company serves up licenses in four different flavors: Business, Premium, Corporate, and Enterprise. A Business license costs $550, and the customer can use it on up to three devices. It includes a session channel with unrestricted endpoints, and the basic functions of a management console. For $1,150 (Premium), or $2,300 (Corporate), more devices can be integrated, and the management console offers more functions in line with this. The Enterprise plan is aimed at requirements of large corporations and for service providers, following consultation.