333

Port 333/tcp carries no widely deployed public service; it is an IANA vendor name reservation ("texar" / "Texar Security Port") with no confirmed modern software behind it, so its correct exposure posture is genuinely Unknown rather than a confident internet-facing, restricted, or internal-only call. IANA registers the name to Eugen Bacic of Texar Corporation, with both 333/tcp and 333/udp carrying identical, otherwise-blank registry fields.

The registry entry itself is minimal: no RFC or reference document, no registration date, and no modification date are published for this row, on either the tcp or udp side. This matches the pattern of an older-era IANA registration where a vendor reserved a service name and port pair without ever publishing an accompanying protocol specification or public documentation, leaving no technical description of how the "security port" actually behaves on the wire.

No current software, appliance, or malware family is documented as actively using 333/tcp. Port-database aggregators such as AuditMyPC explicitly mark it "no" for virus/Trojan association, and the SANS Internet Storm Center does not maintain a dedicated port-activity tracking page for 333, unlike more commonly probed ports such as 3333 or 33330 — suggesting it isn't a notable scanning target in current threat telemetry, though that absence is not proof of complete disuse.

Because the vendor (Texar Corporation) has no ongoing public footprint tied to this port and no successor documentation exists, an analyst encountering a live listener on 333/tcp today should treat it as an unusual finding worth investigating rather than dismiss it as routine, and should not assume it is safe to expose without first identifying the actual process bound to it.

IANA assignment

texar — "Texar Security Port"; reference (blank — no RFC cited); assignee Eugen Bacic (Texar Corporation); dual-registered 333/tcp + 333/udp [Confirmed] — https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=333

Range class

well-known (0–1023)

Prevalence

no dedicated SANS ISC port-activity page for 333 (unlike 3333/33330); no quantified scan-volume data found [Likely] — https://isc.sans.edu/data/port/3333, https://isc.sans.edu/data/port/33330

Related ports

no directly related cluster identified; comparable only as one of many single-vendor IANA name reservations in the 300–399 block [Unknown]

Primary use

vendor-specific security-product name reservation by Texar Corporation; no publicly documented protocol behavior

Other/unofficial uses

none verified; no modern software or infrastructure confirmed to use 333/tcp

Security implications

not flagged as virus/Trojan-associated by AuditMyPC; absence of confirmed modern deployment leaves the exposure profile Unknown rather than confidently internal-only/restricted

Typically seen on

no confirmed hosts or environments identified; historically a Texar Corporation product-specific reservation only [Unknown]

Analyst note

An open/listening port 333/tcp is uncommon and unverified in current usage — investigate rather than assume benign legacy use.

Port 333/udp is officially registered with IANA under the service name texar, described only as "Texar Security Port"; with no public protocol specification, RFC, or currently shipping software implementation verified, it should be treated as an internal, unidentified service rather than assumed safe for public exposure.

The IANA System Ports registry lists texar with assignee/contact Eugen Bacic (associated with the company Texar), and leaves the Reference and Registration Date columns blank — no RFC or dated registration event exists to cite. The identical entry is dual-registered on 333/tcp with the same description, confirming one System Port reservation covering both transports rather than two independent assignments.

Beyond the bare registry label, no independently verifiable technical documentation of the Texar Security Port protocol, and no currently shipping vendor product using it, was found across IANA, consumer port-lookup aggregators, or general web search. Consumer port-scanner databases such as SpeedGuide and AuditMyPC do not flag 333/udp as trojan- or malware-associated, though this reflects the absence of reported incidents rather than a technical guarantee of safety.

IANA assignment

texar — "Texar Security Port"; reference blank (no RFC cited); assignee Eugen Bacic; dual-registered 333/tcp + 333/udp, identical entry [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry (dual-reg line 662); https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml

Range class

well-known (0–1023) [Confirmed]

Prevalence

no Shodan/Censys/CERT/honeypot data or dated scanning statistics specific to 333/udp were located [Unknown]

Related ports

333/tcp (identical dual registration, same description and assignee)

Primary use

registered as "Texar Security Port"; no publicly documented protocol mechanics beyond the registry label [Unknown]

Other/unofficial uses

none verified; no current software/vendor product found still using this port [Unknown]

Security implications

not flagged as trojan/malware-associated by SpeedGuide or AuditMyPC; no dated, port-specific malware incident found

Typically seen on

Unknown — no verified deployments identified

Assignee attribution

assignee identified elsewhere as Eugen Bacic [Likely] — http://www.t1shopper.com/tools/port-number/333/

Analyst note

Treat an open 333/udp as unexpected/unidentified rather than a known benign service, given the absence of any verifiable current implementation or protocol spec.