478

Port 478/tcp carries the IANA-registered service spsc; no protocol specification, expanded description, or real-world application has been found for it, so whether it belongs on the public internet is unknown rather than something this research can confirm one way or the other.

IANA registers 478 on both TCP and UDP under the bare service name spsc, with the description field simply repeating the name, assignee/contact Mike Rieker, a blank Reference (RFC) field, and no registration or modification date recorded in the registry.

An August 2026 web search across the usual port-lookup aggregators (SpeedGuide, WintelGuy, adminsub.net, t1shopper, my-addr.com) found every site mirroring the same bare IANA row, with no named client/server software, no vendor documentation, and no community-sourced sighting of traffic on 478/tcp or 478/udp. Nothing found expands what "spsc" stands for.

One AI-search-generated result linked this port to SNPP (Simple Network Paging Protocol); that claim is uncorroborated and incorrect — SNPP's actual assigned port is 444 — and is rejected here rather than repeated.

The repo's nmap-services-derived corpus records 478/tcp at an open-frequency of exactly 0, a real sampled-but-not-observed-open reading, while 478/udp sits at roughly 0.00061 — both negligible and consistent with an obscure, largely inactive registration.

IANA assignment

spsc — description "spsc" (no expansion given); reference (blank — no RFC cited); assignee Mike Rieker; dual-registered 478/tcp + 478/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry spsc 478/tcp; the IANA Service Name and Transport Protocol Port Number Registry spsc 478/udp

Range class

well-known (0–1023) [Confirmed]

Prevalence

nmap-services open-frequency 478/tcp = 0 (sampled, not observed open); 478/udp ≈ 0.00061 [Confirmed] — this site's own tooling (built from nmap-services)

Related ports

none identified as a paired companion service [Unknown]

Primary use

Unknown — IANA does not expand "spsc" or cite a protocol document, and no independent source located in an August 2026 search identifies the service's function

Other/unofficial uses

none found; port-lookup aggregators (SpeedGuide, WintelGuy, adminsub.net, t1shopper, my-addr.com) all mirror the bare IANA registration with no named software or community-sourced sighting

Security implications

no CVE, exploit writeup, or malware/trojan association found for 478/tcp as of an August 2026 search; auditmypc.com's page returned no retrievable content so no finding is drawn from it

Typically seen on

no deployment pattern identified; an obscure, apparently inactive registration with no evidence of real-world traffic [Unknown]

Analyst note

a response on 478/tcp cannot be attributed to any known application from current research; treat as an anomaly worth investigating rather than assuming a specific benign service.

Port 478/udp carries a service IANA registers only as "spsc"; no protocol specification, vendor documentation, or observed deployment could be found, so what actually runs here — and whether it belongs on the public internet — is unknown rather than confirmed either way.

IANA's Service Name and Transport Protocol Port Number Registry lists 478/udp (and, jointly, 478/tcp) assigned to service name spsc, assignee Mike Rieker, with a blank Reference column and no accompanying description beyond the bare four-letter name itself. No RFC or other formal specification is cited.

Searches of general web sources, port-database aggregator sites, and vendor/forum documentation as of an August 2026 search turned up no expansion of what "spsc" stands for, no software reported to generate traffic on this port, and no CVE or malware-family association tied to 478/udp specifically. This appears to be a thin, individually-assigned legacy IANA registration with essentially no public footprint.

Given the total absence of a documented purpose, an analyst encountering live traffic on 478/udp should treat it as unidentified rather than assume it matches the dormant IANA registration, and investigate context (source host, payload) before drawing conclusions.

IANA assignment

spsc — no description text beyond the service name; reference (blank — no RFC cited); assignee Mike Rieker; dual-registered 478/tcp + 478/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry spsc 478/udp

Range class

system (well-known, 0–1023) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry spsc 478/udp

Prevalence

nmap-services open-frequency 478/udp = 0.00061; 478/tcp = 0 in the same source [Confirmed] — this site's own tooling (port 478 entry)

Related ports

478/tcp (same "spsc" dual registration) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry spsc 478/tcp

Primary use

Unknown — IANA registry gives only the bare service name "spsc" with no expansion or specification found

Other/unofficial uses

None found; targeted searches of vendor docs, forums, and port-database aggregator sites (SpeedGuide, adminsub.net, ports.my-addr.com, portforward.com) surfaced no named application

Security implications

no CVE or malware-family association found as of an August 2026 search; no Shodan/Censys-style internet-exposure writeup specific to this port was found

Typically seen on

Unknown — no reported deployments found [Unknown]

Analyst note

An open port 478/udp has no documented legitimate service behind it — treat any observed traffic as unidentified and worth investigating rather than assuming it matches the dormant IANA registration.