What is RDP - All you need to know by Ericom

What is RDP?

RDP (Remote Desktop Protocol) is a network communications protocol developed by Microsoft, which allows users to remotely connect to another computer. It is an extension of the T.120 protocols that are standards of the ITU (International Telecommunications Union).

What follows is a technical explanation. If you just want the basics, skip to the quick summary and discussion of RDP uses below.

RDP provides a graphical interface for connecting two computers. To use RDP, the computer from which the end user originates the request must be running RDP client software. The computer that is being accessed must be running RDP server software.

RDP client software provided by Microsoft is called Remote Desktop Connection (it used to be called “Terminal Services Client” and you may occasionally see it referred to that way.) Many non-Microsoft RDP clients and servers are available as well, including the open source client rdesktop. rdesktop is a command-line client; there are graphical user interface clients built on top of rdesktop.

In addition, there are ways to implement remote desktops that do not rely on the RDP protocol, such as Ericom Connect.

RDP is available for Windows, Linux, Unix, Mac, iOS, Android, and other operating systems.

In addition to being used to access computers located remotely, Microsoft uses RDP in its Azure cloud-computing solution to serve virtual computers to users.

How it Works

RDP transmits the monitor from the remote server to the client, and keyboard and mouse inputs from the client to the remote server. Communications between the client and the server are highly asymmetrical: a lot of data flows from the server to the client, and not much from the client to the server (the graphical screen information comprises much more data than do keyboard and mouse inputs).

RDP relies on additional protocols to establish the connection between the two devices and to transfer the data. It uses TPKT to enable the exchange of information units, X.224 to set up the connection, and T.125 MCS to enable multiple channels.


Some key features of RDP include:
  • 128-bit encryption
  • 32-bit color support
  • Audio, file system, printer, and port redirection to allow users to connect to local resources from within a terminal session
  • Support for a number of different network topologies

Security Vulnerabilities

RDP has many known security issues. The use of the protocol in Microsoft’s cloud computing solution results in hackers being especially interested in finding and exploiting vulnerabilities. As with any software, it’s important to keep RDP updated to the latest version. Some major known vulnerabilities in earlier RDP versions include:
  • In May 2019 a patch was released to fix a major vulnerability known as “BlueKeep” which allowed for the possibility of remote code execution. According to Microsoft, the vulnerability was “wormable,” meaning it could be self-propagating, which could cause widespread problems.
  • Version 6.1 can reveal all the usernames and pictures of users on the RDP server.
  • In March 2012 a vulnerability that was fixed with a critical security update could have allowed computers to be compromised by worms and unauthenticated clients.
  • Version 5.2 is vulnerable to “man-in-the-middle” attacks, where a hacker can eavesdrop on sessions, or hijack sessions.

Security experts recommend the following precautions for keeping RDP secure:
  • Follow strong password protocols, enable multi-factor authorization, and put in place lock-out policies to block brute force attacks.
  • Put RDP ports behind a firewall that can only be accessed using a VPN.
  • Don't allow RDP to be used for administrator accounts.
  • Specific trusted hosts should be whitelisted.
  • When you are not using RDP, secure the ports it uses.
  • Enable automatic updates for the client/server software you are using so that you can be sure you always have the latest version, in which known security vulnerabilities are fixed.

The Simplified RDP Story

With client software that uses RDP, one can connect to any computer that runs Windows or another compatible operating system. For instance, if you want to access your PC from a laptop or other device, using RDP you can connect to the remote PC, view the content on the remote display, and interact as if working locally on that machine.

Examples of RDP uses:

When you travel for business or go on vacation, sometimes you will need access to your workplace computer. Using Remote Desktop Protocol makes it very easy for you to work from anywhere in the world.
Can’t go to the office today?
There are many reasons that could prevent you from going into the office. However, you still need to fulfill your daily tasks. With RDP, you can access your office computer from the comfort of your home.
Are you a system admin?
Remote Desktop Protocol allows you to perform administrative tasks such as PC tune up, computer troubleshooting, ID protection settings, software installation, printer set-up, email set-up, virus and spyware removal.
Need to give a demo?
You can easily use Remote Desktop Protocol for demonstrations of processes or software applications that are usually accessible only from your office. With RDP you can access the data from any private device.
Want to personalize your remote desktop?
You can customize many elements to create a personalized remote desktop experience including: resolution, screen settings, connection settings, start menu, toolbar, icons, and more.
Need more computing power?
With RDP you can access a powerful workstation in the office using a much less capable machine from home or the road.

Do you have more questions about RDP and how it applies to your specific case? Email our experts.

Learn why Microsoft Remote Desktop access (RDP) alone is not enough and find out more about Ericom’s variety of remote access products.