426
Summary
- // typical exposure
- Anomalous (rarely legitimately open) — No documented protocol or real-world software runs on 426/tcp, so any observed traffic lacks a legitimate baseline and should be treated as anomalous and investigated.
- // analyst note
- with no known legitimate service documented anywhere, any traffic observed on 426/tcp should be treated as anomalous and investigated rather than assumed routine.
- // if you see it open
- No CVE, malware, or honeypot writeup ties to 426/tcp specifically. Because no legitimate service is documented, there is no established baseline of normal use to compare against.
About port 426/tcp.
Port 426/tcp carries no documented, actively used service; IANA reserves the name smartsdp for it, but no protocol specification, vendor software, or real-world deployment could be confirmed, so whether it belongs on the public internet is Unknown — the safest posture is to treat any traffic here as unusual rather than routine business use.
IANA's Service Name and Port Number Registry lists 426 as smartsdp on both TCP and UDP, a dual registration credited to assignee [Marie_Pierre_Belange]. The registry entry carries no Reference (RFC) field, no registration date, and no modification date — all confirmed blank rather than omitted from research.
A web search pass for "smartsdp" and for software known to use port 426 turned up nothing beyond the bare IANA name. The three previously-cited port-list aggregator pages could not be read to confirm their content: speedguide.net returns 403 to every request, adminsub.net returns 522/523 (Cloudflare origin unreachable) on every path tried, and t1shopper.com does not respond at all on either scheme — so no claim about what those pages contain is carried forward. No vendor documentation, forum thread, or blog post identifies an application, game client, or remote-access tool that generates traffic on this port.
No CVE, malware family, or honeypot writeup ties to 426/tcp specifically. Because no legitimate service is documented, there is no established baseline of normal use to compare against, and an open 426/tcp should be investigated case by case.
- IANA assignment
smartsdp— no description beyond the service name; reference blank; assignee[Marie_Pierre_Belange]; dual-registered 426/tcp + 426/udp [Confirmed] — IANA Service Name and Port Number Registry- Range class
- well-known (0–1023) [Confirmed] — IANA registry
- Prevalence
- 0 — nmap-services open-frequency figure of exactly 0.000000: the port was sampled and no open instances were observed [Confirmed] — this site's own tooling
- Related ports
- 426/udp — same
smartsdpdual registration [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry smartsdp 426/tcp + smartsdp 426/udp
Primary use
Unknown — no RFC or vendor protocol specification for smartsdp was located [Unknown]
Other/unofficial uses
Unknown — no community-sourced software sightings found; three previously-cited aggregator pages returned no readable content (speedguide.net 403, adminsub.net 522/523 Cloudflare-origin-unreachable, t1shopper.com no response on either scheme) [Unknown]
Security implications
no CVE, malware, or honeypot association specific to 426/tcp found [Unknown/Likely]
Typically seen on
Unknown — no real-world deployment identified [Unknown]
- Analyst note
- with no known legitimate service documented anywhere, any traffic observed on 426/tcp should be treated as anomalous and investigated rather than assumed routine.
About port 426/udp.
Port 426/udp is registered with IANA under the name smartsdp, but no protocol specification, vendor documentation, or confirmed real-world deployment has been identified for it, so it should be treated as an unknown/unclassified service rather than assumed safe to expose to the public internet.
The IANA Service Name and Transport Protocol Port Number Registry lists smartsdp as dual-registered on both 426/tcp and 426/udp, with assignee contact [Marie_Pierre_Belange] and a blank Reference column — meaning no RFC or other standards document was ever published to explain what the service does. This is typical of early private registrations that predate IANA's stricter documentation requirements.
A dedicated search for vendor documentation, forum threads, honeypot writeups, or CVE records tied to 426/udp turned up nothing beyond the bare IANA name. The two previously-cited third-party port-lookup pages could not be read to confirm their content: speedguide.net returns 403 to every request, and t1shopper.com does not respond at all on either scheme — so no claim about what those pages contain is carried forward. No confirmed software product, client/server implementation, or malware family could be attributed to this port, so observed traffic here should be evaluated on its own merits rather than assumed benign or tied to any specific application.
More broadly, UDP ports are inherently harder to monitor than TCP because they are connectionless and often receive less scanning and firewall scrutiny, a property attackers can exploit for overlooked or covert channels. That general UDP risk applies to 426/udp only as background context, not as evidence of any documented abuse specific to this port.
- IANA assignment
smartsdp— no description beyond the name; Reference column blank; assignee[Marie_Pierre_Belange]; dual-registered 426/tcp + 426/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry smartsdp 426/udp- Range class
- well-known (0–1023)
- Prevalence
- 0.001104 — nmap-services open-frequency figure (roughly 1 opening per 1,000 hosts scanned) [Confirmed] — this site's own tooling
- Related ports
- 426/tcp (same service name, dual-registered under the identical IANA entry) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry smartsdp 426/tcp + smartsdp 426/udp
Primary use
Unknown — IANA provides only the service name, with no protocol description or RFC citation
Other/unofficial uses
none found; no vendor, forum, or scanner writeup identifies real-world software using this port; two previously-cited port-lookup pages returned no readable content (speedguide.net 403, t1shopper.com no response on either scheme) [Unknown]
Security implications
no CVEs or malware associations found specific to 426/udp; general UDP-scanning risk (connectionless, less monitored than TCP) applies only as background context
Typically seen on
Unknown — no confirmed real-world deployments were found [Unknown]
- Analyst note
- A responsive 426/udp lacks any confirmed real-world function in available research; treat activity as unclassified and investigate rather than attribute it to smartsdp or any named application.
Service assignments.
| Name | Protocol | Description | Open frequency |
|---|---|---|---|
| smartsdp | UDP | — | 0.11% |
| smartsdp | TCP | — | 0.00% |
Service assignments from the IANA Service Name and Transport Protocol Port Number Registry, with open-frequency data from nmap-services.