471
Summary
- // typical exposure
- Anomalous (rarely legitimately open) — Port 471/tcp is a dormant 1990s IANA registration for a payment protocol absorbed into MasterCard in 2001 with no evidence of current deployment, so it is essentially never legitimately open and any sighting should be investigated.
- // analyst note
- A responsive port 471/tcp is statistically near-absent and has no known legitimate current use — treat any sighting as anomalous and investigate rather than assume a benign service.
- // if you see it open
- Essentially never legitimately open today; an unexpected listener is anomalous and worth investigating. No malware/trojan association could be established for 471/tcp; auditmypc.com's tcp-port-471 page carries only the site's standard templated framing, not a port-specific verdict. No NVD CVE found as of an August 2026 search.
About port 471/tcp.
Port 471/tcp carries no active modern service; it is a dormant legacy IANA registration and should never be expected open on the public internet or on an internal network today. IANA registers 471 (both tcp and udp) as mondex, description "Mondex," assignee Bill Reding, with both the Reference and Registration Date columns left blank in the registry CSV.
Mondex was an electronic cash / smart-card payment scheme developed by NatWest Bank in the UK starting in 1990, unveiled publicly in 1993, and trialed from 1995 in Swindon, Wiltshire. It let users transfer value peer-to-peer between chip cards via ATMs, card readers, personal wallets, and specialized phones without needing a central transaction authority to authorize each transfer.
Mondex International was absorbed into MasterCard in 2001, and no evidence surfaced of the protocol or an active Mondex service running today. The IANA record reads as a legacy 1990s port assignment that was never withdrawn rather than a currently deployed protocol — no RFC or reference document is cited, and no vendor documentation, blog post, or forum thread describes a modern application generating traffic on this port.
nmap-services open-frequency data in this repo's port-data.json records 471/tcp at exactly 0 (sampled, not observed open) and 471/udp at approximately 0.000478 — both figures are near the floor of the scale, consistent with a dormant, effectively unused registration rather than an actively probed or deployed service.
- IANA assignment
mondex— "Mondex"; reference (blank — no RFC or document cited); assignee Bill_Reding; dual-registered 471/tcp + 471/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry mondex 471/tcp, mondex 471/udp- Range class
- well-known (0–1023) [Confirmed]
- Prevalence
- nmap-services open-frequency 471/tcp = 0 (sampled, not observed open); 471/udp ≈ 0.000478 [Confirmed] — this site's own tooling
- Related ports
- 471/udp (dual registration, same service name); no other closely related ports identified
Primary use
Mondex electronic-cash / smart-card payment protocol (NatWest Bank, UK, developed from 1990, trialed from 1995); no RFC cited
Other/unofficial uses
none identified; Mondex International was absorbed into MasterCard in 2001 and no active service was found
Security implications
essentially never legitimately open today; no malware/trojan association could be established — auditmypc.com's tcp-port-471 page carries only the site's standard templated framing, not a port-specific verdict; no NVD CVE found
Typically seen on
nothing currently — a legacy, effectively unused IANA assignment; an open instance is an anomaly [Likely]
- Analyst note
- A responsive port 471/tcp is statistically near-absent and has no known legitimate current use — treat any sighting as anomalous and investigate rather than assume a benign service.
About port 471/udp.
Port 471/udp carries no confirmed active service; it is a thin, legacy IANA registration with no verifiable software traffic, so there is no basis to call it internet-facing and it should be treated as an anomaly if seen open rather than a normal service.
IANA lists 471/tcp and 471/udp under the service name mondex (description "Mondex"), assignee Bill Reding, dual-registered on both transports, with the Reference column left blank — meaning no RFC or specification is cited for this assignment. No public documentation describing an active Mondex-related protocol on this port was located.
A single community lead surfaced during research: SpeedGuide-style discussion generically links 471/udp to OB-UDPST (Open Broadband-UDP Speed Test, a Broadband Forum tool defined in TR-471). Checking the OB-UDPST project's own documentation, however, shows its actual default control port is 24601 (previously 25000) — not 471. The apparent link looks like numeric confusion with the "TR-471" document number rather than a genuine sighting of traffic on this port, so it is not treated as a valid attribution here.
No CVE, vulnerability-database entry, or documented scanning campaign specific to 471/udp was found as of an August 2026 search. No malware or trojan association is recorded for this port as of the same search.
- IANA assignment
mondex— "Mondex"; reference (blank — no RFC cited in IANA registry); assignee Bill Reding; dual-registered 471/tcp + 471/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry mondex 471/udp- Range class
- system/well-known (0–1023) [Confirmed] — this site's own tooling 471
- Prevalence
- this site's own tooling open-frequency for 471/udp = 0.000478 (~0.048%); 471/tcp = 0 (sampled, not observed open) [Confirmed] — this site's own tooling 471
- Related ports
- 471/tcp (same IANA
mondexdual registration) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry mondex 471/tcp
Primary use
no active, documented protocol found; the IANA mondex registration lists no reference/RFC
Other/unofficial uses
none verified; a candidate lead (OB-UDPST/TR-471) did not check out against its own default-port documentation
Security implications
no CVE or documented scanning campaign specific to this port as of August 2026; no malware/trojan association recorded
Typically seen on
no characteristic host type identified; treat any open instance as an anomaly to investigate [Unknown]
- Analyst note
- An open 471/udp has no confirmed legitimate use case; investigate as an anomaly rather than assume it is expected traffic.
Service assignments.
| Name | Protocol | Description | Open frequency |
|---|---|---|---|
| mondex | UDP | — | 0.05% |
| mondex | TCP | — | 0.00% |
Service assignments from the IANA Service Name and Transport Protocol Port Number Registry, with open-frequency data from nmap-services.