363
Summary
- // typical exposure
- Internal-only — RSVP Tunnel is a resource-reservation/QoS signaling registration intended for use between network devices on internal or trusted infrastructure, not a public-facing service, and no legitimate internet-facing deployment has been documented.
- // analyst note
- treat as an internal signaling registration with essentially no confirmed real-world footprint; an open, internet-facing 363/tcp has no documented legitimate use and is worth investigating.
- // if you see it open
- No documented internet-facing use was found for this port. It is formally registered for RSVP tunneling, a resource-reservation/QoS signaling role that, if used at all, belongs on internal or trusted network infrastructure rather than the public internet. No confirmed software, honeypot data, or scanning telemetry specific to 363/tcp were found, so real-world exposure risk is currently a sourced Unknown rather than a documented threat.
About port 363/tcp.
Port 363/tcp is IANA-registered for "rsvp-tunnel" (RSVP Tunnel), a resource-reservation/QoS signaling registration; no confirmed real-world software has been found using it, so it should stay internal-only rather than be exposed to the public internet.
The IANA Service Name and Transport Protocol Port Number Registry lists 363/tcp (dual-registered with 363/udp) under the well-formed service name "rsvp-tunnel," with description "RSVP Tunnel" and assignee Andreas Terzis. An older underscore variant, "rsvp_tunnel," is marked historic and is no longer usable for common service-discovery mechanisms. The Reference column is blank — IANA cites no RFC for this assignment, so no reference is invented here.
RSVP (Resource Reservation Protocol) signaling is used to reserve bandwidth for real-time traffic paths across a network; a "tunnel" implementation carries that signaling across segments that don't natively support RSVP. This is the formal registration context only — it does not indicate the port sees meaningful real-world traffic today.
A search across web sources, generic port-directory aggregators, and security literature turned up no documented sightings of specific software, honeypot data, or scanning activity on 363/tcp; those gaps are recorded here as sourced abstentions rather than fabricated findings.
- IANA assignment
rsvp-tunnel— "RSVP Tunnel"; assignee Andreas Terzis; dual-registered 363/tcp + 363/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry line 711- IANA reference (RFC)
- blank — no RFC cited in the registry entry [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry line 711
- Registration date
- Unknown (Registration Date column blank for this entry) [Unknown] — the IANA Service Name and Transport Protocol Port Number Registry
- Range class
- well-known (0–1023)
Primary use
registered for RSVP (Resource Reservation Protocol) tunneling — QoS/resource-reservation signaling carried across network segments that don't natively support RSVP; formal registration only, no evidence of common deployment
Common software generating traffic
none found — no credible community-sourced sightings across port-directory aggregators, vendor docs, or forums [Unknown]
Exposure/scanning notes
no security-research, honeypot, or scanning-telemetry sources specific to this port were found [Unknown]
Typically seen on
no confirmed real-world deployments found; theoretically network devices implementing RSVP tunneling internally [Unknown]
- Legacy alias
rsvp_tunnel(underscore), marked historic, not usable for common service discovery [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry lines 713-715- Analyst note
- treat as an internal signaling registration with essentially no confirmed real-world footprint; an open, internet-facing 363/tcp has no documented legitimate use and is worth investigating.
About port 363/udp.
Port 363/udp carries RSVP Tunnel (rsvp-tunnel) traffic, a mechanism for relaying RSVP signaling across tunnel segments that are not themselves RSVP-aware; it is an internal network-infrastructure protocol and should not be exposed to the public internet.
IANA registers rsvp-tunnel on both 363/tcp and 363/udp, assigned to Andreas Terzis, with no populated Reference/RFC field in the registry entry itself. A legacy underscore-variant alias, rsvp_tunnel, also appears in the registry but is marked historic and is not the recommended service name.
The protocol is documented in RFC 2746, "RSVP Operation Over IP Tunnels" — it defines how RSVP (Resource Reservation Protocol) reservation messages can be carried through IP tunnel segments whose routers do not natively support RSVP, so that end-to-end QoS signaling still works across a mixed network path. This places 363/udp squarely in router-to-router or tunnel-endpoint infrastructure signaling rather than end-user application traffic.
No IANA-published registration or modification date exists for this entry; that field is left blank rather than guessed. No CVEs, honeypot reports, Shodan/Censys writeups, or malware associations specific to 363/udp were found during research, and no named vendor software or product was confirmed to commonly generate traffic on this port — secondary port-lookup aggregators (SpeedGuide, t1shopper, EventTracker) simply repeat the IANA/RFC 2746 attribution without adding independent detail.
- IANA assignment
rsvp-tunnel— "RSVP Tunnel"; reference (blank in registry); assignee Andreas Terzis; dual-registered 363/tcp + 363/udp [Confirmed] — IANA the IANA Service Name and Transport Protocol Port Number Registry- Range class
- well-known (0–1023) [Confirmed]
- Registration date
- not published by IANA for this entry [Unknown] — IANA registry (blank column)
- Related ports
- RSVP itself uses IP protocol 46 (not a TCP/UDP port); other QoS/signaling infrastructure ports
Primary use
relays RSVP signaling messages through IP tunnel segments not natively RSVP-aware, per RFC 2746
Common software/applications
none credibly identified in vendor docs, blogs, or forum/community sources during this research pass [Unknown]
Security implications
no CVEs, honeypot, or malware-association data found specific to 363/udp; unexpected exposure should be treated as anomalous given its infrastructure-signaling purpose
Typically seen on
routers or tunnel endpoints implementing RSVP-over-IP-tunnel per RFC 2746; not expected on general end-user hosts
- Legacy alias
rsvp_tunnel(underscore variant), marked historic/deprecated in the registry [Confirmed] — IANA registry- Analyst note
- an open 363/udp outside known tunnel-endpoint infrastructure is unusual and worth investigating; no confirmed malicious use is documented.
Service assignments.
| Name | Protocol | Description | Open frequency |
|---|---|---|---|
| rsvp_tunnel | UDP | — | 0.21% |
| rsvp_tunnel | TCP | rsvp-tunnel | 0.00% |
Service assignments from the IANA Service Name and Transport Protocol Port Number Registry, with open-frequency data from nmap-services.