164

Port 164/tcp is registered with IANA as cmip-agent, described as "CMIP/TCP Agent," with dual registration on 164/udp under the same service name; the assignee and contact are recorded jointly as "[Amatzia_Ben_Artzi]" per the cached IANA registry snapshot, and the Registration Date, Modification Date, and Reference fields are blank in that source — this write-up records that blankness rather than inventing an RFC number or a date. The service pairs with port 163 (cmip-man, the manager side) to implement the Common Management Information Protocol (CMIP) run over TCP/IP, an arrangement sometimes labeled CMOT (CMIP over TCP). CMIP is the OSI network-management protocol standardized as ITU-T X.711 / ISO/IEC 9596-1, implementing the Common Management Information Service (CMIS) that lets a manager station query and control managed network elements through an agent process — port 164 is the agent-side listener in that manager/agent model. CMIP/CMOT saw limited real-world deployment: it was an early-1990s OSI-network-management contender against the eventually-dominant SNMP (ports 161/162), and it persisted longest in telecom OSS/TMN (Telecommunications Management Network) contexts rather than general IP networking. No specific, currently-maintained software implementing a 164/tcp agent listener was identified in this research pass, so that remains Unknown rather than a guessed vendor list. Live SANS Internet Storm Center scan data for the port shows low volume from scattered source IPs and a green (low-concern) threat rating, consistent with the port's legacy, rarely-deployed status — background/opportunistic scan noise rather than active targeting, though that reading is an inference rather than a directly sourced claim.

IANA assignment

cmip-agent — "CMIP/TCP Agent"; assignee/contact "[Amatzia_Ben_Artzi]"; Registration Date, Modification Date, and Reference fields blank in registry; dual-registered 164/tcp + 164/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry-406; https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml

Range class

well-known (0–1023) [Confirmed]

IANA RFC/reference

blank in registry — no RFC cited, none invented [Confirmed absence] — same sources as above

Prevalence

Unknown — no scan-prevalence data (e.g., nmap-services open-frequency) was sourced in this research pass

Related ports

163/tcp (cmip-man, manager side of the same protocol pair) [Confirmed]; 161/162 (SNMP, the protocol that superseded CMIP for general network management) [Likely]

Primary use

agent-side endpoint of CMIP (Common Management Information Protocol) over TCP/IP (CMOT), the OSI network-management protocol (ITU-T X.711/ISO 9596-1) implementing CMIS; pairs with port 163 cmip-man (manager side) [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml; https://en.wikipedia.org/wiki/Common_Management_Information_Protocol

Other/unofficial uses

none specifically identified for this port; CMIP more broadly persisted in early-1990s OSI network-management and later telecom OSS/TMN deployments rather than general IP use

Security implications

legacy, rarely-deployed protocol largely superseded by SNMP (161/162) for network management; live SANS ISC data (accessed 2026-07-10) shows low, scattered-source scan volume and a green/low-concern threat rating, read as background/opportunistic scanning rather than active targeting — an inference, not a directly sourced claim

Typically seen on

no currently common software identified (Unknown); historically associated with telecom OSS/TMN network-management systems rather than general-purpose hosts [Unknown/Likely]

Port 164/udp is registered with IANA as cmip-agent, described as "CMIP/TCP Agent," with an accompanying 164/tcp registration carrying the identical service name and description — dual registration confirmed by both the cached IANA service-names-port-numbers CSV (rows 405–406) and the live IANA service-names-port-numbers.txt registry. The registry lists Amatzia Ben Artzi as both assignee and contact, and leaves the Registration Date, Modification Date, and Reference/RFC fields blank in the current published registry; per no-fabrication policy a blank IANA Reference stays blank rather than standing in for an unlisted RFC. Port 164 is the agent-side counterpart to port 163/tcp+udp (cmip-man, "CMIP/TCP Manager"); together the pair implements CMIP, the Common Management Information Protocol, an OSI/ISO network-management standard contemporaneous with SNMP but built on the OSI management framework rather than SNMP's IP-native model. Organizations wanting OSI-style management without a full OSI stack sometimes carried CMIP over TCP/IP as CMOT (CMIP Over TCP/IP). The protocol saw limited real-world deployment, mainly in telecom and a handful of enterprise network-management products in the 1990s, and was largely superseded by SNMP as the dominant IP management protocol. No actively maintained or currently shipping software was identified in this research pass binding to 164/udp as cmip-agent, so the port should be treated as legacy/effectively unused rather than attributed to a specific current vendor. General port-database aggregators apply a broad "historically associated with trojans" template to many obscure legacy ports, including 164, and that generic warning is not evidence of a specific campaign; live scan telemetry for the port reflects only low, background-level internet-wide sweep activity rather than a documented exploit.

IANA assignment

cmip-agent — "CMIP/TCP Agent"; reference (blank — no RFC cited in IANA registry) [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt (corroborated by cached registry CSV rows 405-406)

Dual registration

164/tcp + 164/udp share identical service name and description [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry (rows 405-406); https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt

Registration date / modification date

Unknown — blank in the current IANA registry, not recorded as an invented date [Unknown]

Range class

well-known (0–1023) [Confirmed]

Primary use

agent side of the CMIP (Common Management Information Protocol) management pair, companion to 163/tcp+udp cmip-man; CMIP is an OSI/ISO network-management protocol, occasionally carried as CMOT (CMIP Over TCP/IP)

Common software

Unknown — no actively maintained or currently shipping software found binding to 164/udp as cmip-agent in this research pass; treat as legacy/effectively unused [Unknown]

Exposure / scanning notes

generic aggregator "historically trojan-associated" warnings apply broadly to many obscure legacy ports and are not campaign-specific; live SANS ISC telemetry shows only low, background-level sweep activity (rolling data, no fixed count recorded) [Likely] — https://isc.sans.edu/data/port/164, https://www.auditmypc.com/udp-port-164.asp, https://www.speedguide.net/port.php?port=164

Assignee / contact

[Amatzia_Ben_Artzi] for both fields [Likely] (single-source, registry-cache read only) — the IANA Service Name and Transport Protocol Port Number Registry