542
Summary
- // if you see it open
- No CVE is recorded in the NVD as of an August 2026 search, and no malware or trojan association is confirmed for this port. AuditMyPC's per-port lookup did not return a retrievable verdict for 542 in this fetch. No protocol specification exists to establish intended exposure, so it stays Unknown; an unexpected open 542/tcp/udp is more plausibly routine background-radiation scanning than use of a documented service.
- // analyst note
- An open 542/tcp is statistically rare and effectively undocumented; verify with banner-grabbing rather than assuming the bare "commerce" label describes real observed traffic.
About port 542/tcp.
Port 542/tcp is registered with IANA under the bare service name "commerce," but no protocol specification, RFC, or documented software implementation exists for it — so whether it belongs on the public internet cannot be answered with confidence, and any exposure should be treated as unconfirmed pending further investigation of the specific host.
IANA's Service Name and Transport Protocol Port Number Registry lists 542/tcp and 542/udp jointly under the name "commerce," assignee Randy Epstein, with the Reference field blank. No accompanying RFC, vendor specification, or protocol document describes what the "commerce" protocol actually does beyond the label itself.
An August 2026 web search found no primary source — vendor documentation, blog post, or forum/support thread — naming specific software that generates traffic on 542/tcp or 542/udp. Generic port-lookup aggregator pages repeat the bare IANA label with templated filler description text, which is not evidence of any real-world deployment and was not treated as one.
Measured open-frequency from the nmap-services corpus is low but nonzero: roughly 0.0013% of scanned hosts for TCP and 0.0675% for UDP, consistent with an obscure, rarely-deployed registered service rather than one seen commonly on the internet.
- Exposure
- Unknown — no protocol specification or credible software attribution exists to judge whether this port is designed for public reach, should be restricted to trusted networks, or should never face the internet.
- Malware association
- none confirmed; AuditMyPC's per-port lookup did not return a retrievable verdict for 542 in this fetch, so no claim is sourced to it either way.
- Anomaly signal
- given the near-total absence of documented deployments, an unexpected open 542/tcp or 542/udp is more plausibly routine internet background-radiation scanning of the full port range than targeted use of a real "commerce" service.
- IANA assignment
commerce— dual-registered 542/tcp + 542/udp; Reference field blank; assignee Randy Epstein [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry commerce 542/tcp- Range class
- well-known (system range, 0–1023) [Confirmed] — this site's own tooling (range: "system")
- Prevalence
- nmap-services open-frequency 542/tcp ≈ 0.000013 (~0.0013%); 542/udp ≈ 0.000675 (~0.0675%) [Confirmed] — this site's own tooling
- Related ports
- part of the low-numbered system-range registered-service cluster near 540–545 [Likely] — this site's own tooling
Primary use
Unknown — bare IANA label "commerce" with no protocol spec, RFC, or vendor documentation found
Other/unofficial uses
none identified
Security implications
no CVE recorded in the NVD as of an August 2026 search; no confirmed malware association; AuditMyPC returned no retrievable per-port verdict for this port
Typically seen on
no confirmed deployments identified
- Analyst note
- An open 542/tcp is statistically rare and effectively undocumented; verify with banner-grabbing rather than assuming the bare "commerce" label describes real observed traffic.
About port 542/udp.
Port 542/udp carries no documented protocol, and it should not be treated as a service that belongs on the public internet — there is no confirmed software or standard tied to it, so an open instance is best assessed case by case rather than assumed safe or assumed malicious.
IANA registers 542 on both tcp and udp under the bare service name commerce, assignee Randy Epstein, with a blank Reference field and no registration date recorded. This is one of many early commercial-internet-era assignments that received a name but no accompanying RFC or protocol specification.
Third-party port-directory sites (WhatPortIs, SpeedGuide, ports.my-addr.com) repeat the IANA label and add unsourced filler about e-commerce, B2B transaction processing, or ERP/payment gateways. That language reads as generic template text applied across many port entries on those sites, not a verified description of an actual deployed protocol or product.
No vendor documentation, blog post, support thread, or client software naming a specific application observed using 542/udp turned up in an August 2026 search. No CVE referencing port 542 is recorded in the NVD as of 2026-08, and no scanning-telemetry or honeypot report specific to this port was found. auditmypc.com's port-542 page could not be retrieved (its interface returned no port-specific content), so its trojan/virus verdict cannot be cited either way.
- Exposure
- Unknown — no protocol specification, vendor/blog/forum source, or confirmed deployment was found for 542/udp; aggregator e-commerce/ERP filler was declined as unsourced, and auditmypc.com's port-542 page could not be retrieved, so exposure cannot be assessed in either direction on that shared evidence base.
- Malware association
- Unknown — no CVE, honeypot report, or IDS signature specific to 542/udp was found as of an August 2026 search, and auditmypc.com's port-542 page did not load port-specific content to cite either way.
- Third-party descriptions
- Port-directory "e-commerce/ERP" language is unsourced template text repeated across many entries on those sites, not verified fact about this port.
- IANA assignment
commerce— description "commerce"; reference (blank); assignee Randy Epstein; dual-registered 542/tcp + 542/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry commerce 542/udp- Range class
- system (0-1023, per the nmap-services frequency data range field "system") [Confirmed] — this site's own tooling 542
- Prevalence
- nmap-services open-frequency for 542/udp = 0.000675 (~0.0675%); 542/tcp = 0.000013 (~0.0013%) [Confirmed] — this site's own tooling 542
- Related ports
- 542/tcp (dual registration, same "commerce" name); other bare-name legacy assignments from the same era
Primary use
no defined protocol or RFC; bare IANA name-only assignment from the early commercial-internet era
Other/unofficial uses
none confirmed; third-party port-directory sites describe generic "e-commerce"/ERP scenarios without citing a real product or deployment
Security implications
no CVE recorded in NVD as of 2026-08; no scanning/honeypot telemetry found specific to this port; auditmypc.com's port-542 page not retrievable
Typically seen on
no confirmed host type; no evidence base to characterize typical usage [Unknown]
- Analyst note
- Port 542/udp has no documented protocol behind its IANA name; exposure is Unknown on the available evidence — neither a confirmed benign service nor a confirmed threat indicator.
Service assignments.
| Name | Protocol | Description | Open frequency |
|---|---|---|---|
| commerce | UDP | — | 0.07% |
| commerce | TCP | — | 0.00% |
Service assignments from the IANA Service Name and Transport Protocol Port Number Registry, with open-frequency data from nmap-services.