Port 4166Joost Peer-to-Peer Protocol

Port 4166 is assigned to the Joost peer-to-peer protocol.

transport: tcp · udp
in transit: cleartext
assignment: official
risk: 1/10
lookups: 0

also known as Joost P2P

Technical Details

what runs on :4166

Joost used this port over both TCP and UDP for its proprietary peer-to-peer protocol. A listener would normally be a Joost client accepting connections from other peers rather than a general-purpose web or streaming server; detailed handshake and framing behavior is not part of a widely documented public standard.

Security Information

exposure of :4166

risk score

1/ 10safe

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

streaming averages 3.0 across 46 ports — this one sits 2.0 below.

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

Internet exposure is generally unnecessary for a discontinued application and should be blocked unless legacy Joost operation is specifically required. Because the protocol is proprietary and obsolete, its authentication and encryption properties should not be assumed from the port assignment alone.

Record

iana registry entry

port: :4166
service: Joost Peer-to-Peer Protocol
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 1/10safe
category: Streaming Media
usage: This port was used by the Joost internet-TV client for peer-to-peer communication and media distribution. Joost is discontinued, so current listeners are expected to be rare and generally limited to legacy installations.
lookups: 0rank 993
added: 2026-09-05
updated: 2026-09-22
references: IANA service name registry — port 4166

Something wrong?

This record is maintained by the engineers who use port 4166. 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 2026-09-22.

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Related Ports

all 46 in streaming →

the 8 most looked-up other ports in streaming — 46 ports carry that label.

port	service	proto	category	risk	views
:8888	GNUmp3d Streaming HTTP	TCP	Web Services	caution	76.3k
:8000	Alternate HTTP / SHOUTcast	TCP	Web Services	caution	45.0k
:8880	Windows Media SOAP Connector	TCP	Streaming	caution	24.3k
:5001	Slingbox	TCP	Streaming	caution	22.4k
:1220	QTSS Admin	TCP	Streaming	safe	20.6k
:19294	Google Talk Voice/Video	TCP	Streaming	caution	16.6k
:12013	Audition Korea Server	TCPUDP	Streaming	caution	14.5k
:9000	SqueezeCenter	TCP	Web Services	caution	14.4k

risk mix of the 8 listed

safe13%
caution88%

0 of 8 encrypted

Port :4166Joost Peer-to-Peer Protocol

Technical Details

Security Information

Related Ports

Port 4166Joost Peer-to-Peer Protocol