Port 3671KNXnet/IP (EIBnet/IP)

KNX building-automation traffic transported over IP for tunneling and routing EIB/KNX telegrams.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 7/10
lookups: 0

also known as efcp, KNX IP

Technical Details

what runs on :3671

KNXnet/IP transports KNX building-automation telegrams over IP, commonly using UDP port 3671 for device discovery and tunneling, with TCP also assigned for implementations that support it. Devices exchange discovery and connection-management messages before carrying KNX cEMI frames; KNXnet/IP routers can also route traffic between IP networks and conventional KNX segments. Classic KNXnet/IP is distinct from newer KNX Secure deployments.

Security Information

exposure of :3671

risk score

7/ 10risk

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

network services averages 3.1 across 946 ports — this one sits 3.9 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 · udp

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

security overview

Classic KNXnet/IP traffic is generally not encrypted or strongly authenticated by default. An Internet-exposed interface may allow discovery, traffic observation, or injection of commands affecting lighting, HVAC, access control, and other building systems; restrict it to trusted networks and use VPNs or KNX Secure where supported.

Record

iana registry entry

port: :3671
service: KNXnet/IP (EIBnet/IP)
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 7/10risk
category: Network Services IoT
usage: This port carries KNXnet/IP, formerly EIBnet/IP, between building-automation controllers, gateways, engineering tools, and KNX devices. It is normally found on internal building-control networks rather than on the public Internet.
lookups: 0rank 994
added: 2026-09-05
updated: 2026-09-05
references: IANA service name registry — port 3671

Something wrong?

This record is maintained by the engineers who use port 3671. 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 2026-09-05.

01edit any field on a page of its own
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edit this record →back to the registry

Related Ports

all 946 in network services →

the 8 most looked-up other ports in network services — 946 ports carry that label.

port	service	proto	category	risk	views
:9080	Groove RPC	TCPUDP	Web Services	caution	70.8k
:6543	Jetnet	UDP	Network Services	caution	65.3k
:5938	TeamViewer	TCPUDP	Remote Access	caution	65.0k
:8291	Winbox MikroTik Admin	TCP	Security	caution	62.9k
:3233	WhiskerControl Protocol	TCPUDP	Network Services	caution	61.9k
:3268	Microsoft Global Catalog (GC)	TCPUDP	Security	caution	54.6k
:135	Microsoft EPMAP	TCPUDP	Security	caution	51.9k
:3128	Tatsoft Default HTTP Proxy	TCP	Web Services	caution	46.8k

risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :3671KNXnet/IP (EIBnet/IP)

Technical Details

Security Information

Related Ports

Port 3671KNXnet/IP (EIBnet/IP)