Port 3951PWG IPP Facsimile

Port 3951 is assigned to PWG IPP-based facsimile services for submitting fax jobs to a network printing or fax device.

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

also known as pwgippfax, IPP FaxOut

Technical Details

what runs on :3951

The assignment identifies a PWG IPP facsimile service, rather than a fax-modem signaling protocol. IPP carries print or fax job operations and attributes over HTTP; standard IPP deployments commonly use TCP port 631, with port 3951 registered for this facsimile service. IPP's usual HTTP transport is TCP; although UDP is also registered for 3951, that alone does not establish it as a normal IPP transport. Implementations and support for this dedicated port are uncommon.

Security Information

exposure of :3951

risk score

2/ 10safe

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

web services averages 3.2 across 187 ports — this one sits 1.2 below.

in transit

cleartext

credentials and payloads are readable by anyone on path

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

IPP traffic is not encrypted by default; deployments can use TLS-protected IPP (IPPS), but encryption and access controls depend on the implementation. If reachable, an inadequately protected endpoint could expose job information or allow unauthorized fax submissions. Because this dedicated service is uncommon and has not appeared open in the cited scan data, it is generally a low-priority internet exposure, though it should still be restricted to intended clients.

Record

iana registry entry

port: :3951
service: PWG IPP Facsimile
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 2/10safe
category: Web Services Network Services
usage: This assignment is for facsimile job submission using the Printer Working Group's Internet Printing Protocol (IPP). It is a niche service; engineers are more likely to encounter general IPP on TCP 631, and port 3951 is not commonly seen open in internet scans.
lookups: 0rank 993
added: 2026-10-02
updated: 2026-10-02
references: IANA service name registry — port 3951

Something wrong?

This record is maintained by the engineers who use port 3951. 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 2026-10-02.

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 187 in web services →

the 8 most looked-up other ports in web services — 187 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 :3951PWG IPP Facsimile

Technical Details

Security Information

Related Ports

Port 3951PWG IPP Facsimile