Port 6209QMTP over TLS

QMTP over TLS is a niche, encrypted mail-transfer service associated with the qmail ecosystem.

transport: tcp · udp
in transit: encrypted
assignment: official
risk: 2/10
lookups: 0

also known as qmtps

Technical Details

what runs on :6209

QMTP (Quick Mail Transfer Protocol) is a mail-delivery protocol distinct from SMTP; QMTP over TLS protects the QMTP exchange with TLS rather than using SMTP's STARTTLS command. The assignment covers TCP and UDP, though TCP is the expected transport for mail delivery and UDP use is not typical. The registered service name indicates TLS, but port 6209 is a niche service rather than a broadly deployed mail standard.

Security Information

exposure of :6209

risk score

2/ 10safe

routine exposure. this port is rarely the way in on its own — keep it patched and logged and move on.

email averages 3.0 across 67 ports — this one sits 1.0 below.

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

TLS protects the connection in transit, but does not by itself prevent abuse of a misconfigured mail server. If this service is exposed, verify that it accepts mail only according to the intended relay and delivery policy; an unintended open relay can be abused for spam. Its low observed prevalence makes unexpected exposure worth investigating.

Record

iana registry entry

port: :6209
service: QMTP over TLS
transport: TCPUDP
encryption: tls / encrypted
assignment: iana registered
risk: 2/10safe
category: Email
usage: Port 6209 is assigned to QMTP over TLS and registered to FEHCom. Engineers are more likely to encounter QMTP in qmail-related mail delivery than on general-purpose mail servers; it is not commonly observed in internet scans.
lookups: 0rank 993
added: 2026-10-10
updated: 2026-10-10
references: IANA service name registry — port 6209

Something wrong?

This record is maintained by the engineers who use port 6209. 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 2026-10-10.

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 67 in email →

the 8 most looked-up other ports in email — 67 ports carry that label.

port	service	proto	category	risk	views
:143	IMAP	TCPUDP	Email	caution	20.7k
:995	POP3S	TCPtls	Email	caution	18.8k
:109	POP2	TCP	Email	caution	17.9k
:2096	cPanel SSL Webmail	TCPtls	Web Services	safe	17.4k
:110	POP3	TCP	Email	caution	15.5k
:993	IMAPS	TCPtls	Email	caution	14.5k
:1352	Lotus Notes RPC	TCP	Email	caution	12.3k
:24	Private Mail	TCPUDP	Email	caution	11.7k

risk mix of the 8 listed

safe13%
caution88%

3 of 8 encrypted

Port :6209QMTP over TLS

Technical Details

Security Information

Related Ports

Port 6209QMTP over TLS