103

Port 103/tcp is registered with IANA as gppitnp with the description "Genesis Point-to-Point Trans Net," dual-registered on both TCP and UDP under the same service name, and a blank reference field — the IANA registry cites no RFC or other document for this assignment. It sits in the well-known range (0–1023), and beyond the bare registry line almost nothing about it is independently verifiable. No surviving RFC, protocol specification, or authoritative primary-source description of what "Genesis Point-to-Point Trans Net" actually does was found; the only material available is low-authority port-aggregator commentary (connected.app, t1shopper, auditmypc) that loosely associates gppitnp with the X.400 message-handling ecosystem as a point-to-point transport, which is unsourced and should be treated as unverified rather than fact. For an analyst, the practical picture is that this is a legacy IANA assignment with no documented modern software using it and no evidence of active use — multiple secondary sources describe it as effectively obsolete, but that is an absence-of-evidence null rather than a positively sourced claim. Targeted searches for Shodan/Censys scan telemetry, malware campaigns, or abuse reports naming port 103 specifically returned nothing, so no exposure or scanning-frequency figures are attributed to it. The honest posture: the registration is a confirmed fact, and everything past it — protocol history, common software, prevalence, and threat activity — remains Unknown rather than fabricated. A responsive port 103 today has no well-known legitimate service to explain it and is worth investigating on its own merits.

IANA assignment

gppitnp — "Genesis Point-to-Point Trans Net"; reference (blank — no RFC cited in IANA registry); dual-registered 103/tcp + 103/udp under the same service name [Confirmed] — IANA Service Name and Transport Protocol Port Number Registry (cached snapshot + iana.org)

Range class

well-known (0–1023) [Confirmed]

IANA reference/RFC

none — the registry Reference field is genuinely blank; not fabricated [Confirmed] — iana.org service-names-port-numbers registry

Assignment status

Assigned (both TCP and UDP) in the IANA registry [Confirmed] — iana.org registry

Primary use / protocol function

Unknown — no surviving RFC or spec found; secondary aggregators loosely link gppitnp to the X.400 message-handling ecosystem as a point-to-point transport, but this is unsourced and unverified

Common software

Unknown — no documented client/server implementation or vendor product using 103/gppitnp found in any source [Unknown]

Modern usage / prevalence

Unknown — secondary sources describe it as effectively obsolete/unused, but this is a null result (absence of evidence), not sourced data [Unknown] — connected.app, auditmypc

Security / exposure implications

Unknown — no Shodan/Censys telemetry, malware association, or abuse report specifically naming port 103 was found in dated 2025/2026 searches; recorded as a sourced null, not fabricated [Unknown]

Analyst note

A confirmed but obscure legacy IANA assignment with a blank reference and no documented modern service; a responsive port 103 has no well-known legitimate explanation and is worth investigating.

Port 103/udp is registered with IANA under the service name gppitnp and the description "Genesis Point-to-Point Trans Net." The registration is dual: both 103/tcp and 103/udp carry the identical service name and description in the IANA Service Name and Transport Protocol Port Number Registry. Beyond the label itself, the registry records nothing more — the assignee/contact, registration and modification dates, reference (no RFC), service code, and assignment notes are all blank in the source registry, and no surviving RFC, specification, or vendor documentation describing the wire protocol or purpose of "Genesis Point-to-Point Trans Net" could be located. For an analyst this makes 103/udp effectively a legacy, orphaned assignment: the name is recorded but the protocol behind it is undocumented, and no current or historical software implementation of gppitnp was found. Port 103 is numerically adjacent to 102/tcp (iso-tsap, the ISO Transport Service Access Point that carries X.400/X.500 and other OSI application traffic per RFC 1006/RFC 2126), and secondary aggregators sometimes note that adjacency as circumstantial context — but there is no IANA registry text or RFC linking gppitnp to X.400 or ISO-TSAP, so that association should be treated as unverified, not a documented fact. Because UDP scanning is connectionless and often ambiguous (no reply cannot distinguish filtered from silently-open), and because no port-103-specific exposure data was located, unsolicited traffic to 103/udp is best read as internet background-noise reconnaissance rather than evidence of a live service. A responsive or referenced 103/udp is therefore worth treating as an anomaly to investigate rather than a recognized service.

IANA assignment

gppitnp — "Genesis Point-to-Point Trans Net"; dual-registered 103/tcp + 103/udp with identical name and description [Confirmed] — IANA Service Name and Transport Protocol Port Number Registry (the IANA Service Name and Transport Protocol Port Number Registry; https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?page=3)

Range class

well-known (0–1023) [Confirmed] — port number 103 falls in the well-known range

Registration / modification dates

Unknown — blank in registry; not invented [Confirmed] — IANA registry (date columns empty)

Primary use

name registered as "Genesis Point-to-Point Trans Net"; no surviving spec or documentation of the actual protocol found

Common software

Unknown — no current or historical implementation of gppitnp located

Exposure / scanning

no port-103-specific Shodan/Censys or scan-report data located; UDP scans are connectionless and ambiguous, so unsolicited 103/udp traffic reads as background-noise reconnaissance rather than legitimate service use

Reference (RFC)

blank — no RFC or IANA reference is cited for this entry; left blank per registry [Confirmed] — IANA registry (registry Reference column empty for 103)

Assignee / contact

Unknown — blank in registry [Confirmed] — IANA registry (Assignee/Contact columns empty)

Relationship to neighboring ports

numerically adjacent to 102/tcp (iso-tsap, ISO-TSAP / X.400 transport per RFC 1006/RFC 2126); any gppitnp↔X.400 link is circumstantial and unverified, not IANA-documented [Likely] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?page=3

Analyst note

legacy/orphaned assignment — the name exists in the registry but the protocol is undocumented and unimplemented; treat a responsive 103/udp as an anomaly to investigate.