646
LDP
Medium RiskTCP/UDP — Other
Port Overview
Port Number
646
Service Name
LDP
Transport Protocol
TCP/UDP
Category
Other
Security Risk
Medium
Port Range
Well-Known (0-1023)
What is Port 646?
Label Distribution Protocol (LDP), defined in RFC 5036, used in MPLS networks to distribute label bindings between Label Switching Routers. Fundamental to MPLS traffic engineering and VPN services.
TCP/UDP
Other
Commonly Used
Security Considerations
Port 646 (LDP) is classified as medium risk. While this service is commonly exposed, consider using encrypted alternatives where available.
Recommendation: Keep the service updated. Monitor logs for unusual activity.