Port 23053Growl Notification Transport Protocol (GNTP)

Growl's TCP protocol for registering notification types and delivering desktop notifications, commonly on port 23053.

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

also known as gntp, Growl protocol

Technical Details

what runs on :23053

GNTP uses a TCP stream, normally on port 23053. Messages begin with a GNTP/1.0 request line naming an operation such as REGISTER or NOTIFY, followed by text headers and a blank line; messages can include sized binary data such as icons. The receiver responds with a GNTP status message. Implementations can use password-based challenge/response authentication, but GNTP traffic is not encrypted by default, so the protocol does not protect notification contents in transit.

Security Information

exposure of :23053

risk score

2/ 10safe

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

network services averages 2.6 across 1,941 ports — this one sits 0.6 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

every listening transport is another surface to filter at the edge

security overview

An exposed receiver may accept unsolicited or spoofed notifications, which can be used for nuisance alerts or social engineering; registration access may also be available depending on configuration. GNTP is not inherently encrypted, so keep it on trusted networks, configure authentication where supported, and block public internet access. There is no general indication that an open GNTP port provides remote administration or code execution.

Record

iana registry entry

port: :23053
service: Growl Notification Transport Protocol (GNTP)
transport: TCP
encryption: cleartext
assignment: iana registered
risk: 2/10safe
category: Network Services
usage: GNTP carries notification registration and delivery between Growl-compatible applications and notification servers, including Growl for Windows and Growl for macOS. Engineers are most likely to encounter it on a local network where applications send alerts to a Growl receiver.
lookups: 0rank 993
added: 2026-10-18
updated: 2026-10-18
references: IANA service name registry — port 23053

Something wrong?

This record is maintained by the engineers who use port 23053. 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 2026-10-18.

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edit this record →back to the registry

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risk mix of the 8 listed

caution100%

0 of 8 encrypted

Port :23053Growl Notification Transport Protocol (GNTP)

Technical Details

Security Information

Related Ports

Port 23053Growl Notification Transport Protocol (GNTP)