219

Port 219/tcp is registered with IANA as uarps, described tersely as "Unisys ARPs," with assignee and contact both listed as [Ashok_Marwaha] and a blank Reference field — no RFC or other document is cited for it in the registry. The identical entry is dual-registered on 219/udp with the same service name, description, assignee, and contact, and the same blank Registration Date, Modification Date, Reference, Service Code, and Assignment Notes columns. Beyond that one-line IANA gloss, no public specification, vendor manual, or technical write-up describing the protocol's actual wire behavior was found; "ARPs" plausibly abbreviates an Address Resolution Protocol variant or a proprietary Unisys application-resolution service tied to the assignee's mainframe/ClearPath or OS 2200 lineage, but this reading is speculative and unconfirmed, so it is not asserted as fact. Scan-prevalence data places the port firmly in obscure territory: Nmap's own service-frequency file shows 219/tcp open in roughly six-hundredths of a percent of scanned hosts (219/udp somewhat higher), and the port does not appear at all in Wikipedia's list of TCP/UDP port numbers. A single low-authority secondary site reports no viruses or trojans currently associated with TCP 219, which is weak corroboration rather than a primary finding, and no CVEs were located. A web-search-surfaced label of "Unisys Message Service" for this port was investigated and deliberately excluded — no citable source substantiated it.

IANA assignment

uarps — "Unisys ARPs"; assignee/contact [Ashok_Marwaha]; dual-registered identically on 219/tcp + 219/udp [Confirmed] — local registry cache (the IANA Service Name and Transport Protocol Port Number Registry, row 540) + https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.csv

IANA Reference field

blank — no RFC or other document cited; not fabricated [Confirmed] — both angles agree (local CSV row 540 + IANA web CSV)

Registration Date / Modification Date

blank in the registry, reported as null (no date invented) [Confirmed] — local registry cache + IANA web registry

Range class

well-known (0–1023) [Confirmed]

Prevalence

nmap-services open-frequency 219/tcp ≈ 0.000063, 219/udp ≈ 0.000395 (rare) [Likely] — https://svn.nmap.org/nmap/nmap-services (single source)

Primary use

Unknown beyond the IANA one-line gloss "Unisys ARPs" — no public protocol spec, vendor doc, or whitepaper found describing actual wire behavior [Unknown]

Common software/implementations

Unknown — no identified server or client implementation found; a possible legacy tie to Unisys ClearPath/MCP or OS 2200 environments (given the assignee) is speculative and unverified [Unknown]

Security implications

absent entirely from Wikipedia's port list; a low-authority secondary source states no viruses/trojans are currently associated with TCP 219 (weak corroboration, not primary); no CVEs found

Unverified claim excluded

a web-search summary surfaced "Unisys Message Service" for this port with no underlying citable source; deliberately excluded from the record [Unknown/rejected]

Port 219/udp is registered with IANA as uarps, described as "Unisys ARPs," with assignee and contact both listed as Ashok Marwaha. The corresponding TCP entry (219/tcp) carries an identical service name and description, confirming this is a genuine dual tcp/udp registration rather than a udp-only assignment. The IANA registry leaves the Reference, Registration Date, Modification Date, Service Code, Unauthorized Use Reported, and Assignment Notes columns blank for this entry, so none of those fields can be sourced — they are reported here as unknown rather than invented. The service name itself ("ARPs," plural) points toward some form of address-resolution service tied to Unisys server or mainframe platforms, plausibly related to the ClearPath/OS 2200 product family that Unisys has marketed under that naming convention, but no primary Unisys technical document was located in this research pass that identifies exactly which software component listens on this port or what wire protocol it speaks. No CVEs or malware associations turned up for 219/udp; general port-lookup reference sites list the assignment but add no independent technical detail beyond what IANA already publishes. The one measured exposure figure available is the nmap-services observed open-frequency, which is very low: ≈ 0.000395 for 219/udp and ≈ 0.000063 for the paired 219/tcp row. Given the vendor-specific, decades-old registration and that very low measured frequency, this port should be treated as a legacy/niche assignment: rare to see open, and any observed traffic on it is more useful as a possible fingerprint of older Unisys infrastructure than as a commonly exploited or well-characterized service.

IANA assignment

uarps — "Unisys ARPs"; reference (blank — no RFC cited in IANA registry); assignee/contact [Ashok_Marwaha]; dual-registered 219/tcp + 219/udp [Confirmed] — IANA Service Name and Transport Protocol Port Number Registry (https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?page=5)

Range class

well-known (0–1023) [Confirmed]

Registration date / modification date / service code / unauthorized-use-reported / assignment notes

all blank in the IANA registry for this entry [Confirmed] — same source; reported as null, not invented

Prevalence

nmap-services observed open-frequency 219/udp ≈ 0.000395 — very low (roughly 4 in 10,000 scanned hosts in the nmap-services sample); the paired 219/tcp row is rarer still at ≈ 0.000063 [Confirmed] — nmap-services dataset

Related ports

none closely related were identified in this pass [Unknown]

Primary use

address-resolution service ("ARPs") associated with Unisys server/mainframe platforms; exact wire protocol and the specific listening component were not confirmed

Other/unofficial uses

[Unknown] — no secondary documentation of alternate uses found in this pass

Security implications

no CVEs or malware associations found for 219/udp; internet-facing exposure is measurably minimal — the nmap-services observed open-frequency is ≈ 0.000395 — though no Shodan/Censys exposure count was located [Likely] — nmap-services dataset; https://www.speedguide.net/port.php?port=219, http://www.t1shopper.com/tools/port-number/219/, https://www.auditmypc.com/tcp-port-219.asp

Typically seen on

legacy Unisys mainframe/ClearPath (OS 2200) family systems, by vendor-naming inference only — no primary Unisys document confirms this link

Analyst note

A vendor-specific, decades-old Unisys assignment with no documented modern exposure; treat an open 219/udp as a possible legacy-Unisys fingerprint rather than a common service, and don't assume malicious intent without further context.