Port 84Common Trace Facility

Port 84 is assigned to the Common Trace Facility (CTF) over TCP and UDP.

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

also known as ctf

Technical Details

what runs on :84

Common Trace Facility is registered on port :84 over tcp and udp to Hugh Thomas. We don't have a technical write-up for it beyond the IANA registry entry.

In nmap's internet-wide scan data this port is found open rarely. What's listening is often not the registered service, so check before you assume.

find what's listening on :84

this machine

# linux
sudo ss -tulpn 'sport = :84'

# macos / bsd
sudo lsof -nP -i :84

# windows (then: tasklist /FI "PID eq <pid>")
netstat -ano | findstr :84

another host

nmap -sV -p T:84 <host>
sudo nmap -sU -sV -p U:84 <host>

run it? the handshake, the implementations you meet in the wild and the flags that matter come from the engineers who do.

add technical details

Security Information

exposure of :84

risk score

1/ 10safe

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

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

no security notes recorded for :84 yet

known exploits, hardening advice, what a compromise looks like — suggest an edit if you know its exposure.

Record

iana registry entry

port: :84
service: Common Trace Facility
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 1/10safe
category: uncategorised
usage: IANA assigns TCP and UDP port 84 to the Common Trace Facility. The assignment is registered to Hugh Thomas, but publicly established deployment and protocol details are not available here.
lookups: 0rank 993
added: 2026-08-26
updated: 2026-08-26
references: IANA service name registry — port 84

Something wrong?

This record is maintained by the engineers who use port 84. 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 2026-08-26.

01edit any field on a page of its own
02a model checks it for accuracy and spam
03clean and confident goes live immediately

edit this record →back to the registry

Related Ports

browse categories →

ports registered around :84, by lookups.

port	service	proto	category	risk	views
:80	HTTP	TCPUDP	Web Services	caution	67.3k
:135	Microsoft EPMAP	TCPUDP	Security	caution	51.9k
:23	Telnet	TCP	Remote Access	caution	34.8k
:83	MIT ML Device	TCP	Network Services	caution	23.1k
:81	Torpark Onion Routing	TCP	Web Services	caution	21.4k
:143	IMAP	TCPUDP	Email	caution	20.7k
:22	SSH	TCPUDPtls	Security	caution	20.3k
:109	POP2	TCP	Email	caution	17.9k

risk mix of the 8 listed

caution100%

1 of 8 encrypted

Port :84Common Trace Facility

Technical Details

Security Information

Related Ports

Port 84Common Trace Facility