420
Summary
- // typical exposure
- Anomalous (rarely legitimately open) — Port 420/tcp is a bare IANA name reservation with no documented protocol or confirmed legitimate software, so it should essentially never be seen open, and any live listener merits investigation as anomalous rather than routine traffic.
- // analyst note
- A response on 420/tcp is uncommon and undocumented — verify manually rather than assuming SMPTE-related, benign, or malicious traffic by default.
- // if you see it open
- Essentially never legitimately open — the registration is a bare IANA name reservation with no documented protocol or confirmed common software. No malware family is attributed to port 420 by any source that resolves, and no current scanning-telemetry source describing active targeting of this port was found.
About port 420/tcp.
Port 420/tcp is registered with IANA under the terse label "smpte" (commonly read as the Society of Motion Picture and Television Engineers), but no RFC or public protocol specification is attached to the entry and no confirmed software is documented running on it — it should not be expected on the public internet, and any host answering on it deserves investigation rather than assumed legitimacy.
The IANA Service Name and Transport Protocol Port Number Registry lists 420 as dual-registered for TCP and UDP, description "SMPTE," assignee/contact handle [Si_Becker], with a blank Reference field. A blank reference is normal for entries that reserve a name without publishing an accompanying protocol document; it is not a missing citation to chase down.
No mainstream, currently-deployed application could be confirmed as generating legitimate traffic on 420/tcp. Community port-reference aggregators were checked but none could be read: t1shopper.com did not respond on either scheme, adminsub.net returned a Cloudflare origin-unreachable error on every path tried, and auditmypc.com redirected to a generic port-search tool with no per-port content — so no third-party claim about this port is carried forward.
No malware family is attributed to port 420 by any source that resolves.
- IANA assignment
smpte— "SMPTE"; reference (blank — no RFC cited); assignee/contact [Si_Becker]; dual-registered 420/tcp + 420/udp [Confirmed] — IANA Service Name and Transport Protocol Port Number Registry- Range class
- well-known (0–1023) [Confirmed]
- Prevalence
- 0.000013 — nmap-services open-frequency figure [Confirmed] — this site's own tooling
- Related ports
- 420/udp — same
smptedual registration [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry smpte 420/tcp + smpte 420/udp
Primary use
no RFC or protocol document is attached; the "smpte" label appears to be a bare IANA name reservation rather than a specified, deployed protocol
Other/unofficial uses
none confirmed; aggregator pages checked (t1shopper.com, adminsub.net, auditmypc.com) returned no readable per-port content [Confirmed negative]
Security implications
essentially never legitimately open; no malware family is attributed to port 420 by any source that resolves [Confirmed negative]
Typically seen on
no typical host type or deployment documented; treat a responsive instance as anomalous [Unknown]
- Analyst note
- A response on 420/tcp is uncommon and undocumented — verify manually rather than assuming SMPTE-related, benign, or malicious traffic by default.
About port 420/udp.
Port 420/udp carries the IANA-registered service name smpte (Society of Motion Picture and Television Engineers), but no public protocol specification or software product documents what actually runs on it — so it has no established case for public-internet exposure, and any live traffic on it deserves scrutiny rather than assumption.
The IANA registry lists this assignment with the plain description "SMPTE," assignee/contact [Si_Becker], and a blank Reference field — no RFC or standards-track document is cited. The same service name is dual-registered on both TCP and UDP (420/tcp and 420/udp), a pattern common to older registry entries.
No vendor documentation, forum thread, or software changelog names a specific application, broadcast-control system, or client generating traffic on 420/udp.
No malware family is attributed to port 420 by any source that resolves. SpeedGuide.net's page returned a 403 and was never read, so no attribution can be made from it.
- IANA assignment
smpte— "SMPTE"; reference (blank — no RFC cited); assignee [Si_Becker]; dual-registered 420/tcp + 420/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry smpte 420/udp- Range class
- well-known (0–1023) [Confirmed] — port number falls below 1024
- Prevalence
- 0.000511 — nmap-services open-frequency figure [Confirmed] — this site's own tooling
- Related ports
- 420/tcp — same
smptedual registration [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry smpte 420/tcp + smpte 420/udp
Primary use
IANA-registered for SMPTE (Society of Motion Picture and Television Engineers) broadcast/media-industry use; no specific protocol document is published in the registry
Other/unofficial uses
none found — no vendor documentation, forum thread, or software changelog names an application using 420/udp [Confirmed negative]
Security implications
no confirmed CVE or malware family; no source that resolves attributes a malware family to port 420 — SpeedGuide.net 403'd (never read) [Confirmed negative]
Typically seen on
broadcast/media-production equipment, if the IANA assignment is actually implemented in practice; not otherwise corroborated [Unknown]
- Analyst note
- An open 420/udp responder has no well-documented legitimate application behind it — investigate rather than assume it is either safe or malicious.
Service assignments.
| Name | Protocol | Description | Open frequency |
|---|---|---|---|
| smpte | UDP | — | 0.05% |
| smpte | TCP | — | 0.00% |
Service assignments from the IANA Service Name and Transport Protocol Port Number Registry, with open-frequency data from nmap-services.