Port 4333ArrowHead Service Protocol (AHSP)

Port 4333 is designated for ArrowHead Service Protocol (AHSP), a little-documented service associated with QuantuMatriX Technologies.

inNetwork Services

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

also known as ahsp

Technical Details

what runs on :4333

ArrowHead Service Protocol (AHSP) is registered on port :4333 over tcp and udp and sctp to QuantuMatriX Technologies, assigned April 2014. 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 never observed open, so if it's open on your network it's more likely a custom or misconfigured service than the registered one.

find what's listening on :4333

this machine

# linux
sudo ss -tulpn 'sport = :4333'

# macos / bsd
sudo lsof -nP -i :4333

# windows (then: tasklist /FI "PID eq <pid>")
netstat -ano | findstr :4333

another host

nmap -sV -p T:4333 <host>
sudo nmap -sU -sV -p U:4333 <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 :4333

risk score

1/ 10safe

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

network services averages 2.6 across 1,525 ports — this one sits 1.6 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 · sctp

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

security overview

no security notes recorded for :4333 yet

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

Record

iana registry entry

port: :4333
service: ArrowHead Service Protocol (AHSP)
transport: TCPUDPSCTP
encryption: cleartext
assignment: iana registered
risk: 1/10safe
category: Network Services
usage: The IANA assignment identifies AHSP on TCP, UDP, and SCTP and lists QuantuMatriX Technologies as the registrant. Its protocol behavior and common deployments are not established in the available information.
lookups: 0rank 993
added: 2026-10-04
updated: 2026-10-04
references: IANA service name registry — port 4333

Something wrong?

This record is maintained by the engineers who use port 4333. 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 2026-10-04.

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

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all 1,525 in network services →

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:3128	Tatsoft Default HTTP Proxy	TCP	Web Services	caution	46.8k

risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :4333ArrowHead Service Protocol (AHSP)

Technical Details

Security Information

Related Ports

Port 4333ArrowHead Service Protocol (AHSP)