Port 12109RETS (Real Estate Transaction Standard) over TLS

RETS over TLS carries authenticated real-estate listing and related data exchanges between MLS servers and client applications.

inWeb Services

transport: tcp · udp
in transit: encrypted
assignment: official
risk: 4/10
lookups: 0

also known as rets-ssl, RETS over SSL

Technical Details

what runs on :12109

RETS is a client-server protocol built on HTTP: clients authenticate and issue requests for operations such as metadata and listing searches, with responses commonly carrying XML or listing data. On a RETS-over-SSL deployment, TLS is established before the HTTP exchange; this is a TCP protocol in normal use, and the registry's UDP entry does not imply a standard RETS-over-UDP mode. Port 12109 is the registered port, but RETS deployments may use other configured ports; RETS is a legacy protocol increasingly superseded by the RESO Web API.

Security Information

exposure of :12109

risk score

4/ 10caution

worth attention. how exposed you are depends on configuration — don't leave it reachable from the internet without a reason.

web services averages 3.1 across 239 ports — this one sits 0.9 above.

in transit

encrypted

payloads are protected on the wire

assignment

official

registered with iana for this service — scanners fingerprint it by number

reachable over

tcp · udp

udp is connectionless — source addresses are trivially spoofed and it is a reflection favourite

security overview

A reachable RETS server is generally intended for authorized MLS clients, not anonymous public browsing. TLS protects traffic in transit, but listing data and account credentials still warrant strong authentication, access controls, and patching; restrict access to this port to expected clients where practical. The registry assignment alone does not establish that RETS is running on a scanned host.

Record

iana registry entry

port: :12109
service: RETS (Real Estate Transaction Standard) over TLS
transport: TCPUDP
encryption: tls / encrypted
assignment: iana registered
risk: 4/10caution
category: Web Services
usage: RETS is a legacy real-estate data exchange protocol used by multiple listing services (MLSs) and the client applications that retrieve their listings and related data. Port 12109 is its registered SSL port, but the assignment is not evidence that a host actually runs RETS there.
lookups: 0rank 993
added: 2026-10-17
updated: 2026-10-17
references: IANA service name registry — port 12109

Something wrong?

This record is maintained by the engineers who use port 12109. Every field on it is editable — change what's wrong, say how you know, and a reviewer publishes it, usually within a minute. Last touched 2026-10-17.

01edit any field on a page of its own
02a model checks it for accuracy and spam
03clean and confident goes live immediately

edit this record →back to the registry

Related Ports

all 239 in web services →

the 8 most looked-up other ports in web services — 239 ports carry that label.

port	service	proto	category	risk	views
:8888	Sun Answerbook & Alt HTTP	TCP	Web Services	caution	123.9k
:8000	Intel Remote Desktop / Alternate HTTP Port	TCP	Web Services	safe	84.3k
:8888	NewsEDGE	TCPUDP	Web Services	caution	83.3k
:8888	HTTP Alternative Port	TCP	Web Services	caution	76.5k
:8888	GNUmp3d Streaming HTTP	TCP	Web Services	caution	76.3k
:9080	Groove RPC	TCPUDP	Web Services	caution	70.8k
:8881	Atlasz Secure Server	TCP	Web Services	caution	67.6k
:80	HTTP	TCPUDP	Web Services	caution	67.3k

risk mix of the 8 listed

safe13%
caution88%

0 of 8 encrypted

Port :12109RETS (Real Estate Transaction Standard) over TLS

Technical Details

Security Information

Related Ports

Port 12109RETS (Real Estate Transaction Standard) over TLS