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Port 5500VNC Viewer Listener

Port 5500 is primarily associated with Virtual Network Computing (VNC) in 'listening' mode, allowing a server-side VNC viewer to wait for remote client connections. This facilitates reverse connections for remote desktop sharing and remote support. Standard VNC normally involves the client connecting to the remote server, but in some deployments, the server initiates a connection back to a listening viewer to bypass firewalls and NAT restrictions..

inRemote AccessNetwork Services
transport
tcp

single transport

in transit
cleartext

payload readable on path

assignment
unofficial

used by convention

risk
4/10

caution

lookups
15,090

rank 217 of 993 · top 22%

Technical Details

what runs on :5500

Port 5500 is used predominantly in VNC software suites, specifically for the 'listening viewer' functionality. In this setup, rather than a client initiating a connection to a server running on a remote system, the remote system (sometimes called the 'server' in typical VNC parlance) initiates a reverse connection back to the user's 'viewer' that is listening on port 5500. This inversion of the typical client/server model is especially useful for connecting to hosts behind restrictive NAT, as it avoids manual port forwarding.

The VNC protocol transmits framebuffer updates, keyboard, and mouse events using a relatively simple protocol based on the RFB (Remote Framebuffer) specification. The connection on port 5500 generally uses plain, unencrypted TCP sessions, depending on the VNC implementation in use, and may require user authentication.

Support tools such as UltraVNC, RealVNC, and TightVNC can use this method for assisting with remote troubleshooting. The VNC software listening on port 5500 waits for incoming reverse connections, which can be a convenience for tech support scenarios but poses certain security and configuration considerations.

Security Information

exposure of :5500

risk score

4/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

remote access averages 4.0 across 110 ports — this one sits level with it.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

unofficial

used by convention, not registered — what answers here varies by deployment

reachable over

tcp

every listening transport is another surface to filter at the edge

security overview

Common Vulnerabilities:

  • Lack of encryption: By default, VNC connections, including those using port 5500, transmit data unencrypted, leaving session data vulnerable to interception or eavesdropping.
  • Weak or missing authentication: Misconfigured VNC servers may lack strong passwords, allowing unauthorized access.
  • Exposure to the internet: Exposing port 5500 directly increases the attack surface, making it a target for brute force attacks.
  • Old software vulnerabilities: Legacy VNC implementations might contain exploitable flaws due to outdated codebases.

Common Mitigations:

  • Use SSH or VPN tunnels to encrypt data transmitted between the VNC viewer and server.
  • Enforce strong, complex passwords and consider multi-factor authentication where supported.
  • Restrict access to port 5500 using firewalls or access control lists, allowing connections only from trusted IPs.
  • Keep VNC software updated to the latest secure versions.
  • Disable unauthenticated reverse connections unless explicitly required and secure the listening viewer appropriately.

Related Ports

all 110 in remote access →

the 8 most looked-up other ports in remote access — 110 ports carry that label.

portservicerisk
:8000Intel Remote Desktop / Alternate HTTP Portsafe
:8888D2GS Admin Consolecaution
:8881Atlasz Secure Servercaution
:5938TeamViewercaution
:8291Winbox MikroTik Admincaution
:8008IBM HTTP Server Admincaution
:135Microsoft EPMAPcaution
:23Telnetcaution

risk mix of the 8 listed

  • safe13%
  • caution88%

0 of 8 encrypted