220-801 · Question #544
Which of the following ports MUST be open to connect to a PC using RDP?
The correct answer is D. 3389. RDP (Remote Desktop Protocol) uses TCP port 3389 by default, and this port must be open on the firewall and host to allow incoming remote desktop connections.
Question
Which of the following ports MUST be open to connect to a PC using RDP?
Options
- A21
- B80
- C443
- D3389
How the community answered
(26 responses)- A4% (1)
- B4% (1)
- D92% (24)
Why each option
RDP (Remote Desktop Protocol) uses TCP port 3389 by default, and this port must be open on the firewall and host to allow incoming remote desktop connections.
Port 21 is used by FTP (File Transfer Protocol) for control channel communication, not remote desktop access.
Port 80 is used by HTTP for unencrypted web traffic and has no role in Remote Desktop connections.
Port 443 is used by HTTPS for encrypted web traffic; while RDP Gateway can tunnel over 443, the native RDP connection requires port 3389.
Microsoft's Remote Desktop Protocol (RDP) listens on TCP port 3389 by default on Windows systems. For a remote desktop connection to succeed, port 3389 must be allowed through any firewalls between the client and the target PC, and Remote Desktop must be enabled on the target machine. This port is well-known and should be restricted to trusted IP ranges to reduce attack surface.
Concept tested: Remote Desktop Protocol default port number
Source: https://learn.microsoft.com/en-us/windows-server/remote/remote-desktop-services/clients/remote-desktop-allow-access
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