188

Port 188/tcp is registered with IANA under the service name mumps, described as "Plus Five's MUMPS," with both the Assignee and Contact fields listing Hokey Stenn. The registry entry is dual-registered: 188/udp carries an identical service name, description, and assignee/contact, differing only in transport protocol. The Registration Date, Modification Date, Reference, Service Code, and Assignment Notes columns are all blank in the current IANA registry, so no RFC reference, service code, or dated allocation event can be honestly attributed to this entry — it predates the registry's practice of recording those fields and is already present in RFC 1700 (October 1994), which lists it in the general assigned-ports table without citing it as this record's formal Reference. MUMPS (Massachusetts General Hospital Utility Multi-Programming System, also called "M") is a programming language and hierarchical database technology historically central to healthcare information systems, with a lineage running through products like InterSystems Caché/IRIS and early VA VistA deployments. "Plus Five Computing Services" was a MUMPS-technology vendor that registered this port for its own MUMPS network service, but no currently-maintained software could be confirmed as actively using port 188 today, and no CVEs, Shodan data, or scanner prevalence figures specific to this port were located — it does not appear on common scanned/exploited port lists. An observed listener on 188/tcp today should be investigated case-by-case rather than assumed to run the original 1990s Plus Five service.

IANA assignment

mumps — "Plus Five's MUMPS"; assignee/contact Hokey Stenn; dual-registered 188/tcp + 188/udp with identical fields apart from transport [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt (cross-verified against cached registry CSV the IANA Service Name and Transport Protocol Port Number Registry, rows for port 188)

Registration/Modification date

blank in the IANA registry — not recorded, no date fabricated [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt

IANA Reference (RFC)

blank. RFC 1700 (Lottor/Reynolds & Postel context aside, this one is the "Assigned Numbers" STD, Oct 1994) lists port 188/mumps in its general port table but is not cited as the IANA Reference for this record, so no RFC reference is recorded [Confirmed] — https://www.ietf.org/rfc/rfc1700, https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt

Range class

well-known (0–1023) [Confirmed]

Prevalence / scanning data

Unknown — no nmap-services frequency figure, CVE, or Shodan/Censys report specific to port 188 was found; it does not appear on common scanned-port lists [Unknown]

Primary use

registered for MUMPS (Massachusetts General Hospital Utility Multi-Programming System, "M") database/network services from vendor Plus Five Computing Services, an early networked-database protocol

Modern software using this port

Unknown — no currently-maintained MUMPS/M implementation (GT.M, YottaDB, InterSystems Caché/IRIS) was confirmed to default to port 188 [Unknown]

Security context

no known modern vulnerability history or active-exploitation record found; relevance today is chiefly historical/administrative rather than operational [Likely]

Port 188/udp is IANA-registered under the service name mumps with the description "Plus Five's MUMPS," assignee and contact "Hokey Stenn," and blank Registration Date, Modification Date, and Reference (no RFC) fields. The identical entry appears for 188/tcp, confirming a dual tcp/udp registration under the same service name rather than a udp-only assignment. The name refers specifically to a vendor product — Plus Five Software's network-access layer for MUMPS (also called M), a decades-old programming language and integrated database technology whose best-known lineage runs through the U.S. Veterans Affairs' VistA electronic health record system and various financial-industry systems; the port-188 registration is the vendor's access protocol, not the MUMPS language itself. No RFC, current vendor documentation, CVE, or Shodan-reported banner tied to 188/udp was located in this pass; independent port-lookup aggregator sites (auditmypc, speedguide, t1shopper, portsmaster) simply restate the IANA registry entry without adding verifiable technical detail. One automated web-search summary asserted port 188 is used for "SNMP Trap" — that claim is factually wrong (SNMP trap is port 162) and was rejected rather than reported, illustrating why aggregator/AI summaries need cross-checking against the primary IANA registry before inclusion. Given the niche, legacy-vendor nature of the registration and the absence of exploit literature, real-world internet exposure on 188/udp today is negligible — the nmap-services dataset measures its observed open-frequency at roughly 0.000527, against 0.000000 on 188/tcp.

IANA assignment

mumps — "Plus Five's MUMPS"; reference (blank — no RFC in registry); assignee/contact Hokey Stenn; dual-registered 188/tcp + 188/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry (udp row) and :462 (tcp row)

Range class

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

Registration/modification dates

blank in the cached IANA CSV; left null rather than invented [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry

Prevalence

nmap-services observed open-frequency 188/udp ≈ 0.000527 (very low — roughly 5 in 10,000 scanned hosts in the nmap-services sample) [Confirmed] — nmap-services dataset; the dual-registered 188/tcp row records 0.000000 in the same dataset [Confirmed] — nmap-services dataset

Related ports

188/tcp (identical dual registration, same service name/assignee) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry

Primary use

vendor-specific network-access protocol for Plus Five Software's MUMPS (M) database product; MUMPS itself is a legacy language/database technology (VA VistA lineage, financial systems), but this registration names the vendor product specifically

Other/unofficial uses

none independently verified; aggregator sites only restate the IANA entry; one AI-generated summary incorrectly claimed "SNMP Trap" (actual SNMP trap port is 162) and was excluded as unreliable

Security implications

no CVEs, known exploits, or Shodan-documented banners found specific to 188/udp; no evidence of notable current scanning/honeypot activity targeting it

Typically seen on

legacy/vendor MUMPS-database deployments, if any remain internet-facing; otherwise expected to be closed [Unknown]