142

Port 142/tcp is registered with IANA under the service name bl-idm, described simply as "Britton-Lee IDM," with both the assignee and contact fields listing [Susie_Snitzer]. The registration carries no RFC or other reference document — the Reference column is blank in the IANA registry, and no Registration Date, Modification Date, or Service Code is recorded either, so those fields are honestly reported as unknown rather than guessed. The same service name is dual-registered on UDP: 142/udp shares the identical description, assignee, and contact, with no fields distinguishing the two transport-layer entries beyond the protocol column itself. "Britton-Lee IDM" refers to a relational database-machine product line from Britton Lee, Inc. (later Sharebase), a company that built specialized hardware "database machines" in the 1980s intended to offload SQL query processing from a host computer — IDM most likely stands for "Intelligent Database Machine," one of the company's flagship product names, though IANA's own text does not spell that out. The product line is long obsolete and effectively absent from modern deployments. Passive internet-scan telemetry shows only low-volume, untargeted background probing of TCP/142, and a widely circulated legacy malware-port list associates the port with a trojan named "NetTaxi," though no dated or current incident evidence corroborates active exploitation. A legitimately open port 142 today would be unusual and worth investigating as either scanner noise, a coincidental listener, or (rarely) a genuine legacy Britton-Lee system.

IANA assignment

bl-idm — "Britton-Lee IDM"; Reference column blank; assignee/contact [Susie_Snitzer]; dual-registered 142/tcp + 142/udp (identical description/assignee on both rows) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry (local registry copy); https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt

Range class

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

Registration/modification dates and IANA reference/RFC

Unknown — all blank in the IANA registry; left null rather than invented [Confirmed] (blankness itself is confirmed; the underlying values are Unknown)

Prevalence

nmap-services observed open-frequency 142/tcp ≈ 0.000013 — the dataset's lowest nonzero step [Confirmed] — nmap-services dataset; sibling 142/udp ≈ 0.000428, some thirty-three times higher. Both negligible, matching the SANS ISC picture of low-volume background probing rather than real deployment

Related ports

Unknown — no related-port relationship identified by either research angle

Primary use

Britton-Lee IDM — a 1980s-era relational database-machine hardware product from Britton Lee, Inc.; product line is obsolete and not in current active use [Likely] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt (IANA gives only the short description; the product-history context is a reasonable but not IANA-sourced inference)

Other/unofficial uses

none identified as current or actively maintained

Security implications

SANS ISC's port-142 page shows low-volume, non-targeted background scanning, threat level "green" as of the 2026-07-10 snapshot; the same static registered-services table also lists a historical "NetTaxi" trojan association for TCP/142, but this is an uncorroborated legacy list entry, not a dated incident report

Typically seen on

Unknown — no current legitimate deployment identified; a live listener today would most plausibly be a rare legacy Britton-Lee system, scanner artifact, or coincidental/unrelated service [Likely]

Analyst note

An open port 142 is rare and its legitimate use (an obsolete 1980s database-machine product) is essentially extinct; treat a live response as scanner noise, a coincidental service, or worth manual investigation rather than assuming malicious intent from the "NetTaxi" association alone, since that claim is uncorroborated.

Port 142/udp is registered with IANA as bl-idm, described as "Britton-Lee IDM," with Susie_Snitzer listed as both assignee and contact. The entry is dual-registered: the identical service name and description also cover 142/tcp, with no distinguishing per-transport notes in the registry. IANA's Registration Date, Modification Date, Reference, Service Code, Unauthorized Use Reported, and Assignment Notes columns are all blank for this row — the registry simply does not carry a per-entry assignment date the way an RIR autnum record does, so no date is recorded here. Britton-Lee IDM refers to the Intelligent Database Machine, a proprietary database-server appliance sold in the 1980s by Britton Lee, Inc. (later renamed ShareBase Corporation in 1989, acquired by Teradata in June 1990), typically paired with the Omnibase/SmartStar software stack and attached to DEC VAX midrange systems. No contemporary production use of the protocol is documented, and the company itself no longer exists in that form. Live background-noise scanning against port 142 (both transports) is visible in SANS ISC's rolling telemetry, consistent with generic internet-wide sweeps rather than any real bl-idm service base; separately, port databases flag TCP port 142 (not UDP specifically) with a historical, non-current association to the "NetTaxi" trojan. No CVE or advisory ties specifically to 142/udp.

IANA assignment

bl-idm — "Britton-Lee IDM"; assignee/contact Susie_Snitzer; Registration Date, Modification Date, Reference, Service Code, Unauthorized Use Reported, and Assignment Notes all blank in the registry [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry (line 362); cross-checked against https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt

Dual registration

142/tcp and 142/udp share the identical service name and description in the registry [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry (lines 361–362)

Range class

well-known (0–1023) [Confirmed]

Prevalence

the nmap-services dataset records bl-idm on 142/udp with an open-frequency of 0.000428 — roughly four hundredths of one percent of sampled hosts — against 0.000013 for 142/tcp, which is the dataset's lowest nonzero step; rare but nonzero, consistent with the background-noise reading rather than a deployed bl-idm service base

[Confirmed] — nmap-services dataset

Related ports

142/tcp (identical registry entry, dual-registered) [Confirmed]

Primary use

legacy, effectively dormant reservation for Britton-Lee's Intelligent Database Machine (IDM), a proprietary 1980s database-server appliance typically run with Omnibase/SmartStar and attached to DEC VAX hosts; no documented modern (2020s) production use

Security implications

SANS ISC shows nonzero day-to-day background-noise scan activity on port 142 (both TCP and UDP), consistent with generic mass port sweeps rather than active bl-idm exposure; separately, port-to-malware lookups associate TCP port 142 (not UDP) with the historical "NetTaxi" trojan — a past association flag, not current infection evidence; no CVE/advisory specific to 142/udp was found

Typically seen on

no legitimate modern hosts identified; any observed traffic is best explained as internet background-noise scanning

Reference/RFC

blank in the IANA registry — no RFC is cited for this entry, left blank rather than invented [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.txt

Company history

Britton Lee, Inc. renamed to ShareBase Corporation in 1989 and was acquired by Teradata in June 1990, after which the IDM line was discontinued [Likely, single-source] — https://en.wikipedia.org/wiki/Britton_Lee,_Inc.

Analyst note

an open/responsive 142/udp today is not expected from a legitimate service; treat it as scan noise unless corroborated by other evidence, and note the TCP-side NetTaxi trojan association is historical and transport-specific to TCP, not UDP.