Port 6443Kubernetes API Server

Port 6443 is the common secure HTTPS endpoint for the Kubernetes API server, used to manage and query a cluster.

transport: tcp · udp
in transit: encrypted
assignment: official
risk: 8/10
lookups: 0

also known as sun-sr-https, kube-apiserver

Technical Details

what runs on :6443

Kubernetes commonly configures the API server's secure port as TCP 6443. It serves the Kubernetes API over HTTPS: clients make HTTP requests after a TLS handshake, and the server applies configured authentication and authorization before accepting operations. The API is used for cluster state queries and changes; load balancers may expose the same endpoint on another port, often 443. The IANA registration lists both TCP and UDP, but the Kubernetes API server uses TCP, not UDP. This common use is separate from the IANA sun-sr-https assignment.

Security Information

exposure of :6443

risk score

8/ 10risk

treat as sensitive. widely scanned and regularly exploited when reachable — restrict it to known sources.

network services averages 2.6 across 1,713 ports — this one sits 5.4 above.

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

An exposed Kubernetes API endpoint can reveal cluster information and, if credentials or authorization are weak or misconfigured, allow changes that amount to control over workloads and cluster resources. TLS protects traffic in transit but does not make the endpoint safe to expose by itself. Restrict access to trusted networks or clients, require strong authentication and authorization, and keep the control plane patched; avoid unrestricted public access.

Record

iana registry entry

port: :6443
service: Kubernetes API Server
transport: TCPUDP
encryption: tls / encrypted
assignment: iana registered
risk: 8/10risk
category: Network Services Cloud
usage: Kubernetes commonly uses TCP 6443 as the secure endpoint for its API server, which handles cluster management requests from administrators, controllers, and other components. The IANA assignment is named sun-sr-https and describes a Service Registry Default HTTPS Domain; that assignment is distinct from Kubernetes use.
lookups: 0rank 993
added: 2026-10-10
updated: 2026-10-10
references: IANA service name registry — port 6443

Something wrong?

This record is maintained by the engineers who use port 6443. Every field on it is editable — change what's wrong, say how you know, and a reviewer publishes it, usually within a minute. Last touched 2026-10-10.

01edit any field on a page of its own
02a model checks it for accuracy and spam
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edit this record →back to the registry

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risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :6443Kubernetes API Server

Technical Details

Security Information

Related Ports

Port 6443Kubernetes API Server