355
Summary
- // typical exposure
- Internal-only — DATEX-ASN is a control-centre-to-control-centre ITS data-interchange protocol meant for dedicated government/DOT infrastructure, not designed for public reachability, so it should never be exposed directly to the internet.
- // analyst note
- an initial AI-search claim that this port is used by I2P was checked against the IANA registry and found inaccurate — I2P has no fixed low port; treat unsourced "I2P" attributions for 355 as wrong [Confirmed] — IANA registry
- // if you see it open
- Niche control-centre-to-control-centre ITS protocol with no known CVEs or dated threat-intelligence incidents identified. A generic auditmypc.com page shows a boilerplate 'no known malware association' template that is not treated as a genuine dated security event. An unexpected open port 355 outside ITS/traffic-management contexts is anomalous and worth investigating.
About port 355/tcp.
Port 355/tcp is registered to datex-asn, a niche ASN.1-encoded data-interchange protocol built for transport-management centres; it should stay confined to trusted government or DOT infrastructure rather than being exposed to the public internet.
The IANA registry lists the service name as datex-asn with description "DATEX-ASN," assignee Kenneth Vaughn, and a blank reference column — no RFC or specification link is cited in the registry entry itself. The port is dual-registered for both TCP and UDP.
DATEX-ASN is standardized as ISO 14827-2:2005, the ASN.1-encoded companion to ISO 14827-1:2005, which together define "subscription" and "publication" style message exchange between control centres for transport and traffic-management data. It sits in the intelligent transport systems (ITS) domain, used mainly by specialized government and transportation-agency systems rather than general-purpose software.
No credible vendor documentation, blog post, or forum thread was found naming specific commodity software that commonly binds to port 355 in practice, so no named-application list can be responsibly produced. An earlier web-search synthesis claiming the port is used by I2P was checked against the IANA registry directly and found to be inaccurate — I2P has no fixed low port — and is discarded rather than reported as fact.
- IANA assignment
datex-asn— "DATEX-ASN"; reference (blank — no RFC cited in IANA registry); assignee Kenneth Vaughn; dual-registered 355/tcp + 355/udp [Confirmed] — IANA Service Name and Transport Protocol Port Number Registry- Range class
- well-known (0–1023) [Confirmed]
- Prevalence
- no nmap-services open-frequency data found for 355/tcp or 355/udp in researched sources [Unknown]
- Related ports
- none specifically identified in research [Unknown]
Primary use
ASN.1-encoded data-interchange protocol for intelligent transport systems (ITS) transport/traffic-management centres, per ISO 14827-2:2005
Other/unofficial uses
none identified in research [Unknown]
Security implications
niche control-centre protocol with no known CVEs or dated threat-intel; an unexpected open port 355 is anomalous outside ITS contexts
Typically seen on
intelligent transport systems (ITS) / traffic-management-centre infrastructure, government/DOT systems
- Analyst note
- an initial AI-search claim that this port is used by I2P was checked against the IANA registry and found inaccurate — I2P has no fixed low port; treat unsourced "I2P" attributions for 355 as wrong [Confirmed] — IANA registry
About port 355/udp.
Port 355/udp is registered to datex-asn, a niche ASN.1-encoded data-interchange protocol built for transport-management centres; it should stay confined to trusted government or DOT infrastructure rather than being exposed to the public internet.
IANA lists port 355 as dual-registered for both TCP and UDP under the same datex-asn name, with a blank Reference field. DATEX-ASN is standardized as ISO 14827-2:2005, the ASN.1-encoded companion to ISO 14827-1:2005, which together define subscription- and publication-style message exchange between control centres for transport and traffic-management data in the intelligent transport systems (ITS) domain.
No dated security incident, exploit, or scanning campaign specific to port 355 was found in general port and threat-overview sources. Because DATEX-ASN is a niche control-centre protocol confined to ITS/traffic-management-centre and government/DOT infrastructure rather than general-purpose deployment, an analyst who observes traffic on 355/udp should treat it as low-prevalence and unusual rather than assume it maps to a known commodity application.
Some low-quality port-lookup aggregator sites list generic associations for this port (for example CORBA or I2P), but those associations recur as templated text across many unrelated ports on the same sites and are not treated as credible, attributable sightings here.
- IANA assignment
datex-asn— "DATEX-ASN"; reference (blank — no RFC cited in IANA registry); assignee Kenneth Vaughn; dual-registered 355/tcp + 355/udp [Confirmed] — IANA Service Name and Transport Protocol Port Number Registry- Range class
- well-known (0–1023) [Confirmed] — port number falls in the IANA well-known range
- Prevalence
- Unknown — no nmap-services or telemetry figures surfaced for this port [Unknown]
- Related ports
- 355/tcp (same
datex-asndual registration) [Confirmed] — IANA registry
Primary use
ASN.1-encoded data-interchange protocol for intelligent transport systems (ITS) transport/traffic-management centres, per ISO 14827-2:2005
Other/unofficial uses
none found in vendor or community sources [Unknown]
Security implications
no CVEs, exploits, or scanning campaigns specific to port 355 found; DATEX-ASN is a niche ITS/traffic-management-centre protocol with no known CVEs or dated threat-intelligence incidents identified [Unknown]
Typically seen on
intelligent transport systems (ITS) / traffic-management-centre infrastructure, government/DOT systems
- Analyst note
- An open/active port 355 outside ITS/traffic-management-centre contexts is anomalous; treat it as worth investigating as misconfiguration or an unrelated service rather than assuming a known general-purpose application.
Service assignments.
| Name | Protocol | Description | Open frequency |
|---|---|---|---|
| datex-asn | UDP | — | 0.08% |
| datex-asn | TCP | — | 0.00% |
Service assignments from the IANA Service Name and Transport Protocol Port Number Registry, with open-frequency data from nmap-services.