Port 8384Syncthing GUI (TCP)

TCP 8384 commonly serves Syncthing’s web GUI; UDP 8384 is assigned to the Marathon Transport Protocol.

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

also known as marathontp, Marathon Transport Protocol

Technical Details

what runs on :8384

The IANA assignment is for UDP and names the Marathon Transport Protocol; its handshake, framing, and deployment behavior are not well documented. Separately, Syncthing commonly listens on TCP 8384 for its HTTP-based web GUI, normally bound to 127.0.0.1:8384 by default. The GUI can be configured to listen on other addresses and to use HTTPS. Syncthing's file synchronization and local discovery use other ports, not this GUI port.

Security Information

exposure of :8384

risk score

7/ 10risk

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

file transfer averages 3.3 across 201 ports — this one sits 3.7 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

udp

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

security overview

The UDP assignment has no established public exposure profile. For TCP 8384, exposing the Syncthing GUI to the internet can grant access to administrative settings and synced-device configuration; the default localhost binding limits network exposure, but a deliberately external listener should have GUI authentication enabled and HTTPS configured. Do not assume an open UDP 8384 socket is Syncthing—the common Syncthing use is TCP.

Record

iana registry entry

port: :8384
service: Syncthing GUI (TCP)
transport: UDP
encryption: cleartext
assignment: iana registered
risk: 7/10risk
category: File Transfer Network Services
usage: IANA assigns UDP 8384 to the Marathon Transport Protocol for Inertia Systemes, but that assignment has no broadly established deployment. On TCP, port 8384 is commonly the default Syncthing web GUI, usually bound to localhost.
lookups: 0rank 993
added: 2026-10-14
updated: 2026-10-14
references: IANA service name registry — port 8384

Something wrong?

This record is maintained by the engineers who use port 8384. 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 2026-10-14.

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Related Ports

all 201 in file transfer →

the 8 most looked-up other ports in file transfer — 201 ports carry that label.

port	service	proto	category	risk	views
:9080	Groove RPC	TCPUDP	Web Services	caution	70.8k
:17500	Dropbox LAN Sync	TCPUDP	File Transfer	caution	43.7k
:548	Apple Filing Protocol	TCP	File Transfer	caution	36.8k
:7000	Vuze HTTPS Tracker	TCPtls	Security	caution	28.9k
:1337	PowerFolder P2P	TCP	Security	caution	27.1k
:9001	SharePoint Authoring		Web Services	caution	26.3k
:8080	FilePhile Relay	UDP	File Transfer	caution	25.6k
:1337	WASTE Encrypted Sharing	TCP	Security	caution	22.9k

risk mix of the 8 listed

caution100%

1 of 8 encrypted

Port :8384Syncthing GUI (TCP)

Technical Details

Security Information

Related Ports

Port 8384Syncthing GUI (TCP)