566

Port 566/tcp is IANA-registered under the service name streettalk, which matches StreetTalk, the naming and directory service for Banyan VINES, a proprietary enterprise network operating system from Banyan Systems that was popular in the late 1980s and 1990s. However, IANA's registry entry does not itself state that this port implements Banyan's StreetTalk protocol; it only records the coincident service-name string, and Banyan VINES historically ran primarily over its own VIP (VINES Internet Protocol) network layer rather than classic TCP/IP. It has no legitimate place on the public internet, and because Banyan VINES is long discontinued, an open port 566 seen today more likely reflects a misconfigured or unrelated listener than genuine StreetTalk traffic.

IANA's Service Name and Transport Protocol Port Number Registry lists port 566 as dual-registered on TCP and UDP for streettalk, with the description field simply repeating the service name. No assignee, registration date, modification date, or RFC/document reference is recorded for this entry.

Third-party Banyan VINES documentation describes StreetTalk as the network's global naming directory, mapping human-readable hierarchical names in the form Item@Group@Organization to network addresses, and notes it was also involved in validating login credentials during client authentication. Banyan Systems ceased VINES development in the early 2000s, and no current mainstream software was found using port 566 for this purpose.

The nmap-services corpus records an open-frequency of 0 for both 566/tcp and 566/udp — sampled but not observed open, consistent with an obsolete service. No specific malware or trojan family tied to port 566 could be confirmed from a credible source as of a September 2026 search; generic trojan-port aggregator sites list the port only inside bulk databases, which is not itself evidence of an association.

Exposure

streettalk/Banyan VINES is a legacy enterprise directory service that should never be reachable from the public internet, and even on an internal network it has no modern reason to be open.

Legitimacy today

Banyan VINES is discontinued, so a responsive port 566 is more plausibly a misconfigured or unrelated listener than genuine StreetTalk traffic — treat it as worth investigating rather than assuming legitimacy.

Prevalence

nmap-services open-frequency is 0 for both 566/tcp and 566/udp — sampled, not observed open, consistent with an obsolete service.

IANA assignment

streettalk — description "streettalk"; no assignee, registration date, or reference recorded; dual-registered 566/tcp + 566/udp [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/tcp; streettalk 566/udp

Range class

well-known (0–1023) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/tcp

Prevalence

nmap-services open-frequency 566/tcp = 0 and 566/udp = 0 (sampled, not observed open) [Confirmed] — this site's own tooling

Related ports

566/udp (dual-registered streettalk sibling) [Confirmed] — the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/udp

Primary use

StreetTalk, the Banyan VINES naming/directory service mapping Item@Group@Organization names to network addresses

Other/unofficial uses

none confirmed; Banyan VINES is discontinued and no current software use of port 566 was found [Unknown]

Security implications

legacy/obsolete service; an open port 566 today is more likely a misconfigured or unrelated listener than real StreetTalk traffic [Likely] — https://www.rhyshaden.com/banyan.htm; no specific malware/trojan family confirmed as of a September 2026 search

Typically seen on

legacy Banyan VINES enterprise networks (historical); otherwise unexpected [Likely]

Analyst note

treat an open port 566 today as worth investigating rather than assuming legitimate StreetTalk service, given Banyan VINES' end-of-life status [Likely] — https://www.rhyshaden.com/banyan.htm

Port 566/udp carries no confirmed active service; it is IANA-registered under the name "streettalk" but should not be exposed to the public internet given the absence of any documented legitimate current use. The IANA Service Name and Transport Protocol Port Number Registry lists 566/udp (and 566/tcp) as "streettalk" with no accompanying RFC or specification document, no assignee description, and no reference column entry.

The service name matches StreetTalk, the distributed name and directory service that was the core naming component of Banyan Systems' VINES (Virtual Integrated NEtwork Service) network operating system from the 1980s through the 1990s. VINES used StreetTalk to maintain a global directory of network resource names across servers on a site.

However, IANA's registry entry does not itself state that this port implements Banyan's StreetTalk protocol over IP/UDP; it only records the coincident service-name string. Banyan VINES historically ran primarily over its own VIP (VINES Internet Protocol) network layer rather than classic IP/UDP, so the documented relationship between the 566 IANA registration and actual Banyan StreetTalk directory traffic is thin. Banyan VINES itself is a legacy, effectively discontinued platform, and no current software, vendor documentation, or community sighting was found tying live traffic to this port as of a September 2026 search.

Exposure

No documented legitimate public-facing use; this is a legacy, IANA-registered name-service port tied to a discontinued network operating system rather than an internet-facing protocol.

Service identity

IANA registers the name "streettalk" on 566/udp with no RFC, no assignee description, and no reference document (the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/udp).

Historical association

The name corresponds to Banyan VINES' StreetTalk directory service, but no source confirms this specific IANA UDP assignment carries actual VINES StreetTalk traffic.

Malware/CVE

No CVE is recorded in the NVD and no malware or scanning-campaign association naming port 566 was found as of a September 2026 search.

Scanning exposure

General full-range UDP sweeps would be expected to occasionally probe any registered port.

IANA service name

streettalk [Confirmed] (the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/udp)

IANA RFC/reference

None recorded; the Reference column is blank in the registry [Confirmed] (the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/udp)

Dual registration

Also registered as streettalk on 566/tcp [Confirmed] (the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/tcp)

Malware association

None found in NVD or malware-tracking sources as of a September 2026 search [Unknown]

Port

566 [Confirmed] (the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/udp)

Transport

UDP [Confirmed] (the IANA Service Name and Transport Protocol Port Number Registry streettalk 566/udp)

Historical service

Name matches Banyan VINES' StreetTalk directory/naming service, and Banyan VINES historically ran primarily over its own VIP network layer rather than classic IP/UDP [Likely] (https://www.rhyshaden.com/banyan.htm)

Current active use

Unknown; no vendor documentation, blog, or forum sighting of live traffic was found [Unknown] (as of a September 2026 search)