483

Port 483/tcp carries the IANA-registered service "ulpnet," but with no documented protocol behind the name and essentially no observed real-world traffic, it should not be expected on the public internet and any open instance is worth treating as anomalous.

IANA lists 483/tcp (and identically 483/udp) as "ulpnet," assignee Kevin_Mooney, with the registry's Description column simply repeating the service name. No RFC, specification, or registration date is recorded for this entry — the blank fields reflect the actual state of the registry, not an omission in this write-up.

Third-party port-lookup aggregators (SpeedGuide, Tecniwao, t1shopper, adminsub.net) all mirror the bare IANA entry without adding technical detail, and no forum threads, vendor documentation, or client software describing real deployments of ulpnet were found as of an August 2026 search.

A Juniper Networks ThreatLabs page documents an application signature named "ULPNET" for its SRX/MX/vSRX App-ID engine, but its listed ports (UDP 5246-5247, UDP 3386, UDP 3544, TCP 3386, TCP 434) do not include 483, so despite the matching name it is not evidence of traffic on this specific port.

Measured prevalence backs up the obscurity: the repo's nmap-services-derived port-data.json records an open-frequency of exactly 0 for 483/tcp — a real sampled reading of "not observed open," not a missing value — while 483/udp sits near 0.000461.

IANA assignment

ulpnet — description field repeats "ulpnet" with no expanded text; reference (blank); assignee Kevin_Mooney; dual-registered 483/tcp + 483/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry ulpnet 483/tcp

Range class

well-known/system (0–1023) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry ulpnet 483/tcp

Prevalence

nmap-services open-frequency 483/tcp = 0 (sampled, not observed open); 483/udp ≈ 0.000461 [Confirmed] — this site's own tooling (port 483)

Related ports

no direct related-port cluster identified for this service [Unknown]

Primary use

registered service name only; no protocol specification, RFC, or behavioral description is published by IANA or found elsewhere [Confirmed registration / Unknown function] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.csv

Other/unofficial uses

none documented; a Juniper ThreatLabs "ULPNET" App-ID signature exists but names a different port set, not 483

Security implications

no confirmed deployed software; essentially never observed open; SANS ISC shows only low background scan noise; no verified malware/trojan association

Typically seen on

no known deployment identified; not tied to a specific OS or product [Unknown]

Analyst note

an open 483/tcp is registered but functionally undocumented and statistically almost never observed — investigate rather than assume routine service traffic.

Port 483/udp carries the IANA-registered service name ulpnet, but no protocol specification or documented software has ever been confirmed to use it, so it should not be expected as a normal production service and any observed traffic warrants investigation rather than treatment as a known, safely-exposable application.

The IANA registry lists 483 as registered for both TCP and UDP under the single name ulpnet, with assignee [Kevin_Mooney] and a blank Reference column — no RFC or other specification document is cited. No registration or modification date is recorded for the entry.

Beyond the bare label, no independent protocol description for "ulpnet" could be located as of an August 2026 search. Juniper's ThreatLabs application-signature catalog has an entry titled "ULPNET" that mentions IANA port 483 TCP/UDP in its descriptive text, but the same page's actual live-detection port list (UDP 5246-5247, 3386, 3544; TCP 3386, 434) does not include 483 — an apparent template artifact, so this page cannot be used to confirm real-world traffic on 483/udp specifically.

SANS Internet Storm Center's port-483 activity page shows only low-volume, unattributed internet background-scan hits with a "Threat Level: green" rating and no recorded CVE or user comments, consistent with routine internet-wide port sweeping rather than exploitation of a known service.

IANA assignment

ulpnet — blank description beyond the service name; reference (blank); assignee [Kevin_Mooney]; dual-registered 483/tcp + 483/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry ulpnet 483/udp

Range class

well-known (0–1023) [Confirmed]

Prevalence

nmap-services open-frequency 483/udp = 0.000461; 483/tcp = 0 (sampled, not observed open) [Confirmed] — this site's own tooling (port 483)

Related ports

483/tcp (same ulpnet registration, dual-registered) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry ulpnet 483/tcp

Primary use

Unknown — no protocol specification or expansion of "ulpnet" is published beyond the bare IANA label

Other/unofficial uses

none confirmed; Juniper ThreatLabs lists a "ULPNET" application signature that mentions IANA port 483 in its description, but its own live detection port list does not include 483, so it is not treated as a confirmed use

Security implications

low-volume, green-rated internet background scanning only; no CVE on file; no malware/trojan association documented

Typically seen on

Unknown — no host or software type is confirmed to run this service [Unknown]

Analyst note

An open 483/udp has no confirmed legitimate application behind it after decades of IANA registration — treat unexpected traffic as worth investigating rather than assuming a known benign service.