Port 3550Secure SMPP

Port 3550 is assigned to Secure SMPP, a protected transport for SMS messaging between clients and SMS centers.

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

also known as ssmpp, SMPP over TLS

Technical Details

what runs on :3550

Secure SMPP is SMPP carried over a secure transport, ordinarily TLS: after the TLS handshake, peers exchange SMPP PDUs, including bind requests and responses, using SMPP's length-prefixed framing and command sequence numbers. SMPP normally uses TCP; although IANA lists both TCP and UDP for port 3550, UDP is not a customary transport for SMPP. The commonly cited unencrypted SMPP port is 2775.

Security Information

exposure of :3550

risk score

4/ 10caution

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

network services averages 2.7 across 1,412 ports — this one sits 1.3 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

An exposed listener may accept SMS-gateway binds and, depending on its configuration, allow message submission or delivery. Keep it restricted to known gateway peers, require strong bind credentials and TLS, and monitor for unauthorized binds or message sending; no port-specific vulnerability is implied by the assignment.

Record

iana registry entry

port: :3550
service: Secure SMPP
transport: TCPUDP
encryption: tls / encrypted
assignment: iana registered
risk: 4/10caution
category: Network Services Mobile
usage: Secure SMPP carries SMS gateway traffic between an external short-message entity and a service center (SMSC). It is an uncommon assignment; the registry lists it under Cormac Long, and it was not observed open in the cited Nmap scan data.
lookups: 0rank 993
added: 2026-09-30
updated: 2026-09-30
references: IANA service name registry — port 3550

Something wrong?

This record is maintained by the engineers who use port 3550. 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 2026-09-30.

01edit any field on a page of its own
02a model checks it for accuracy and spam
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edit this record →back to the registry

Related Ports

all 1,412 in network services →

the 8 most looked-up other ports in network services — 1,412 ports carry that label.

port	service	proto	category	risk	views
:9080	Groove RPC	TCPUDP	Web Services	caution	70.8k
:6543	Jetnet	UDP	Network Services	caution	65.3k
:5938	TeamViewer	TCPUDP	Remote Access	caution	65.0k
:8291	Winbox MikroTik Admin	TCP	Security	caution	62.9k
:3233	WhiskerControl Protocol	TCPUDP	Network Services	caution	61.9k
:3268	Microsoft Global Catalog (GC)	TCPUDP	Security	caution	54.6k
:135	Microsoft EPMAP	TCPUDP	Security	caution	51.9k
:3128	Tatsoft Default HTTP Proxy	TCP	Web Services	caution	46.8k

risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :3550Secure SMPP

Technical Details

Security Information

Related Ports

Port 3550Secure SMPP