Port 563NNTPS

NNTPS (Network News Transfer Protocol Secure) is the encrypted version of NNTP, which facilitates the distribution, querying, retrieval, and posting of Usenet articles using TLS/SSL encryption to ensure privacy and integrity during data transmission..

transport
tcp · udp

2 transports registered

in transit
encrypted

payload protected on the wire

assignment
official

registered with iana

risk
2/10

safe

lookups
18,095

rank 146 of 993 · top 15%

Technical Details

what runs on :563

NNTPS, operating on port 563, is the secure variant of the Network News Transfer Protocol (NNTP). Unlike standard NNTP, which transmits data in plaintext, NNTPS wraps all communication within SSL/TLS tunnels, providing data confidentiality against eavesdropping and ensuring message integrity. The encryption is initialized at connection time, similar to how HTTPS secures HTTP.

The NNTP protocol itself is a client-server communication model functioning mainly for distributing and reading network news articles on Usenet. Commands and article data are exchanged following a defined command set. When secured with TLS/SSL as with NNTPS, the protocol remains the same functionally, but gains a security layer protecting the interpretation of authentication credentials and messages.

NNTPS is typically supported by news readers to establish a trusted channel between clients and news servers, especially where sensitive discussions take place or compliance requirements mandate encryption. It is widely deployed in environments prioritizing secure content delivery and privacy in newsgroup communications.

Security Information

exposure of :563

risk score

2/ 10safe

routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.

web services averages 3.9 across 112 ports — this one sits 1.9 below.

in transit

encrypted

payloads are protected on the wire

assignment

official

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

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

Common vulnerabilities:

  • SSL/TLS misconfigurations such as supporting outdated protocols (SSLv2/SSLv3) or weak ciphers can expose communications to downgrade or man-in-the-middle attacks.
  • Improper certificate validation can allow impersonation of news servers, leading to data interception.
  • Default or weak authentication credentials transmitted through secured channels nonetheless become a risk if user management is poor.

Common mitigations:

  • Enforce strong SSL/TLS configurations, supporting only modern protocol versions (TLS 1.2+) and secure cipher suites.
  • Use valid, trusted certificates and enable strict certificate validation on clients.
  • Apply strong authentication policies and enforce password complexity.
  • Regularly patch news server software to address emerging vulnerabilities.
  • Implement monitoring to detect anomalous traffic or failed authentication attempts.

the 8 most looked-up other ports in web services — 112 ports carry that label.

risk mix of the 8 listed

  • safe13%
  • caution88%

0 of 8 encrypted