74

Port 74/tcp is registered with IANA as netrjs-4 with the description "Remote Job Service," assignee and contact both Bob Braden, and a blank reference field (dual-registered on TCP and UDP). The name belongs to NETRJS (Network Remote Job Service), an early ARPANET-era batch-job protocol developed at UCLA's Campus Computing Network (CCN) that let remote host users submit batch jobs to UCLA's IBM 360/91 mainframe running the RJS subsystem of OS/360. NETRJS used a small bank of logical channels — operator input/output, card-reader input, printer output, and card-punch output — and ports 71–74 were the original ARPANET sockets later mapped onto Internet port numbers; port 74 is the fourth of those channels. The protocol design is described in RFC 88 (NETRJS, 13 January 1971), which predates the modern TCP/IP port system and documents ARPANET socket conventions rather than the IANA port-74 assignment directly — the IANA registry itself cites no RFC for this entry. The protocol is obsolete and has not been in general use since the ARPANET era; modern IBM Network Job Entry (NJE) over TCP/IP persists in z/OS but uses different ports (e.g. 175) and protocols. For an analyst, port 74 is essentially inert: SANS ISC lists it at threat level green with no documented CVEs, no active software, and no significant scanning or exploitation activity in public threat intelligence. Any traffic seen on port 74 today is far more likely to be opportunistic noise or misclassified traffic than a live NETRJS service.

IANA assignment

netrjs-4 — "Remote Job Service"; reference (blank — no RFC cited in IANA registry); assignee/contact Bob Braden; dual-registered 74/tcp + 74/udp [Confirmed] — IANA Service Name and Transport Protocol Port Number Registry (the IANA Service Name and Transport Protocol Port Number Registry–173)

Range class

well-known (0–1023) [Confirmed]

Related ports

the NETRJS channel cluster 71–74 (netrjs-1 through netrjs-4)

Primary use

fourth channel (channel 4) of the NETRJS / Remote Job Service batch-job protocol (UCLA CCN, ARPANET era)

Protocol origin

NETRJS — Network Remote Job Service, UCLA Campus Computing Network, for batch job submission to an IBM 360/91 running the OS/360 RJS subsystem; ports 71–74 mapped from original ARPANET sockets

Other/unofficial uses

none documented; modern IBM NJE over TCP/IP uses different ports (e.g. 175), not 74

Protocol status

obsolete/historic; not in general use since the ARPANET era

Security implications

negligible — no known CVEs, no active software, no documented exploit code; SANS ISC threat level green, no significant scanning activity

Typically seen on

nothing in modern environments; any observed traffic is most likely benign noise or misclassified traffic

RFC reference

RFC 88 (13 Jan 1971) describes the original NETRJS protocol but predates modern port assignments; IANA lists no RFC for port 74 [Confirmed] — rfc-editor.org/rfc/rfc88; IANA registry

Analyst note

Port 74 is statistically inert today. Treat a response as anomalous noise or misclassification rather than a live Remote Job Service; legitimate use is essentially nonexistent.

Port 74/udp is registered with IANA as netrjs-4 with the description "Remote Job Service," assignee and contact Bob Braden, and a blank reference field (dual-registered on TCP and UDP — 74/tcp carries the identical netrjs-4 assignment). NETRJS (Network Remote Job Service) is an ARPANET-era protocol from UCLA's Campus Computing Network for batch job submission to IBM mainframes through virtual remote batch terminals. A NETRJS session ran over a Telnet connection and multiplexed several logical channels — a card-reader channel for submitting jobs, printer and punch channels for retrieving output, and an operator console channel — so a remote site could behave like a local card-reader/line-printer station. The protocol is documented in RFC 740 (November 1977), which obsoletes the earlier RFCs 189 and 599; RFC 740 carries no formal IETF standards standing and the IANA registry itself cites no RFC reference for this port. Ports 71–74 form the netrjs-1 through netrjs-4 family of related Remote Job Service variants, with 74 the highest-numbered. For an analyst the protocol is entirely historical: batch remote job entry over ARPANET is obsolete and there is no known modern software that uses this port, so any responsive netrjs-4 listener today is anomalous. SANS ISC shows only low-level broad-sweep reconnaissance scanning on port 74 (threat level green as of June 2026), consistent with indiscriminate internet scanners probing every port rather than targeted exploitation, and there are no CVEs or active exploits specific to netrjs-4. An open response on UDP/74 in a modern environment is best read as a misconfiguration or an unrelated service binding, and standard guidance is to block inbound UDP/74 at the perimeter.

IANA assignment

netrjs-4 — "Remote Job Service"; reference (blank — no RFC cited in IANA registry); assignee/contact Bob Braden; dual-registered 74/tcp + 74/udp [Confirmed] — IANA Service Name and Transport Protocol Port Number Registry (the IANA Service Name and Transport Protocol Port Number Registry line 173; 74/tcp line 172)

Range class

well-known (0–1023)

Registration metadata

registration_date / modification_date blank in registry [Confirmed] — IANA registry (date columns blank, not fabricated)

Related ports

the netrjs family (71/72/73/74) and other legacy ARPANET remote-job services

Primary use

ARPANET-era Network Remote Job Service — batch job submission/output retrieval to IBM mainframes via virtual remote batch terminals over Telnet (RFC 740, Nov 1977; obsoletes RFC 189 + RFC 599); legacy/obsolete

Protocol family

netrjs-1..netrjs-4 occupy ports 71–74; 74 = netrjs-4 variant

Other/unofficial uses

none known; no active modern implementation

Security implications

legacy assignment with no active service; SANS ISC shows only low-level broad-sweep scanner activity (threat level green, June 2026); no CVEs or netrjs-4-specific exploits; any open UDP/74 today is anomalous — treat as misconfiguration or unrelated binding and block inbound at perimeter

Typically seen on

nothing in modern environments; an open listener is an anomaly

Analyst note

An open port 74 is statistically rare and tied to an obsolete ARPANET batch-job protocol — investigate as a misconfiguration, decoy, or unrelated service rather than legitimate netrjs use.