Port 3974Remote Applicant Tracking Service

TCP and UDP port 3974 is assigned to the Remote Applicant Tracking Service, with no widely documented deployment.

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

also known as xk22

Technical Details

what runs on :3974

Remote Applicant Tracking Service is registered on port :3974 over tcp and udp to Marc Castelluccio, assigned August 2005. 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 :3974

this machine

# linux
sudo ss -tulpn 'sport = :3974'

# macos / bsd
sudo lsof -nP -i :3974

# windows (then: tasklist /FI "PID eq <pid>")
netstat -ano | findstr :3974

another host

nmap -sV -p T:3974 <host>
sudo nmap -sU -sV -p U:3974 <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 :3974

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 :3974 yet

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

Record

iana registry entry

port: :3974
service: Remote Applicant Tracking Service
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 1/10safe
category: uncategorised
usage: The IANA assignment identifies TCP and UDP 3974 as the Remote Applicant Tracking Service. It was registered to Marc Castelluccio; no common deployment is established by the available information.
lookups: 0rank 993
added: 2026-10-02
updated: 2026-10-02
references: IANA service name registry — port 3974

Something wrong?

This record is maintained by the engineers who use port 3974. 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 2026-10-02.

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 :3974, by lookups.

port	service	proto	category	risk	views
:3978	OpenTTD Master Server	TCPUDP	Gaming	caution	12.5k
:3999	Norman Scanning Service	TCPUDP	Security	caution	9.9k
:4007	PrintBuzzer Socket Server	TCP	Network Services	caution	8.2k
:4001	Microsoft Ants	TCP	Gaming	caution	7.7k
:3945	EMCADS	TCPUDP	Security	caution	7.6k
:4018	Protocol Info & Warnings	TCPUDP	Network Services	caution	6.7k
:3979	OpenTTD	TCPUDP	Gaming	caution	4.4k
:4000	Diablo II	TCPUDP	Gaming	caution	4.3k

risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :3974Remote Applicant Tracking Service

Technical Details

Security Information

Related Ports

Port 3974Remote Applicant Tracking Service