Port 1863Microsoft Notification Protocol

Port 1863 is primarily used by the Microsoft Notification Protocol (MSNP), which underpins the connectivity for Microsoft’s instant messaging clients such as MSN Messenger and legacy .NET Messenger services. This protocol facilitates presence information, instant messaging, and notification delivery to users on these platforms..

transport
tcp

single transport

in transit
cleartext

payload readable on path

assignment
official

registered with iana

risk
4/10

caution

lookups
15,934

rank 187 of 993 · top 19%

Technical Details

what runs on :1863

The Microsoft Notification Protocol (MSNP) is a proprietary protocol developed by Microsoft to enable communication between Messenger clients and Microsoft's servers. It manages user authentication, presence status updates, message exchange, and notifications related to contacts, such as online/offline status changes. Initially designed for MSN Messenger, MSNP underwent multiple iterations (MSNP2 through MSNP21) featuring enhancements in security and performance.

MSNP operates predominantly over TCP port 1863, initiating and maintaining persistent connections to facilitate real-time message delivery. It uses a text-based command syntax similar to HTTP for command and response exchanges, easing parsing and development. Payloads for messages and notifications are encapsulated within these commands, enabling flexible and extensible communication.

Over time, this protocol was supplemented or replaced by more modern solutions integrated into Microsoft’s messaging infrastructure, transitioning eventually to Skype and Microsoft Teams, which leverage different services. However, remnants of MSNP usage might still be found in legacy systems or deprecated services relying on compatibility layers.

Security Information

exposure of :1863

risk score

4/ 10caution

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

voice and chat averages 3.9 across 120 ports — this one sits 0.1 above.

in transit

cleartext

credentials and payloads are readable by anyone on path

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp

every listening transport is another surface to filter at the edge

security overview

Common Vulnerabilities:

  • Exploitation of unencrypted communication channels due to lack of built-in encryption, leading to interception or man-in-the-middle attacks.
  • Potential for buffer overflow vulnerabilities in poorly implemented client or server software parsing MSNP commands.
  • Abuse for spamming and phishing attacks via unsolicited instant messages through exposed services.

Common Mitigations:

  • Disable this port externally unless the legacy MSN/.NET Messenger services are in active use.
  • Implement strict firewall rules to limit inbound and outbound traffic on port 1863.
  • Use network monitoring to detect unauthorized or anomalous activity over this port.
  • Transition to modern, encrypted messaging platforms that enforce strong authentication and secure transport.
  • Keep any client software fully updated and patched to reduce parsing-related vulnerabilities.

the 8 most looked-up other ports in voice and chat — 120 ports carry that label.

risk mix of the 8 listed

  • caution100%

1 of 8 encrypted