Port 5423virtualuser

An IANA-assigned TCP/UDP port for the VIRTUALUSER service, registered to Chad Williams.

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

Technical Details

what runs on :5423

virtualuser is registered on port :5423 over tcp and udp to Chad Williams. 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 :5423

this machine

# linux
sudo ss -tulpn 'sport = :5423'

# macos / bsd
sudo lsof -nP -i :5423

# windows (then: tasklist /FI "PID eq <pid>")
netstat -ano | findstr :5423

another host

nmap -sV -p T:5423 <host>
sudo nmap -sU -sV -p U:5423 <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 :5423

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 :5423 yet

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

Record

iana registry entry

port: :5423
service: virtualuser
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 1/10safe
category: uncategorised
usage: Port 5423 is assigned for the VIRTUALUSER service on both TCP and UDP. The registry provides no product, protocol, deployment, or usage details beyond the registration to Chad Williams.
lookups: 0rank 993
added: 2026-09-06
updated: 2026-09-06
references: IANA service name registry — port 5423

Something wrong?

This record is maintained by the engineers who use port 5423. 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 2026-09-06.

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 :5423, by lookups.

port	service	proto	category	risk	views
:5450	OSIsoft PI System Client	TCP	Databases	caution	14.3k
:5402	MFTP Protocol	TCPUDP	File Transfer	caution	11.0k
:5432	PostgreSQL	TCPUDP	Databases	caution	10.8k
:5405	NetSupport Manager	TCPUDP	Remote Access	caution	9.3k
:5445	Cisco Unified Video Advantage	UDP	Network Services	caution	7.8k
:5421	NetSupport Manager	TCPUDP	Security	caution	7.7k
:5433	Bouwsoft Server	TCP	Web Services	caution	6.3k
:5431	PARK AGENT	TCPUDP	—	safe	0

risk mix of the 8 listed

safe13%
caution88%

0 of 8 encrypted

Port :5423virtualuser

Technical Details

Security Information

Related Ports

Port 5423virtualuser