Port 538GNUstep Distributed Objects Mapper

GNUstep's service mapper for locating distributed-object services on a host or network.

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

also known as gdomap

Technical Details

what runs on :538

gdomap uses both TCP and UDP on port 538 to provide a directory mapping service names to the network endpoints used by GNUstep distributed objects. GNUstep clients query the mapper when establishing remote NSConnection-style object connections, while servers register their names and listening ports. The protocol is specific to GNUstep rather than a general-purpose service-discovery standard, and normal deployments do not provide transport encryption.

Security Information

exposure of :538

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 3.3 across 808 ports — this one sits 1.3 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

Do not expose gdomap broadly to the internet. Its cleartext, specialized discovery and registration traffic can reveal GNUstep services and may permit unwanted queries or registration attempts depending on the daemon version and configuration; restrict it to trusted hosts or networks.

Record

iana registry entry

port: :538
service: GNUstep Distributed Objects Mapper
transport: TCPUDP
encryption: cleartext
assignment: iana registered
risk: 2/10safe
category: Network Services System
usage: Port 538 is used by gdomap, the GNUstep Distributed Objects Mapper daemon. GNUstep applications use it to register and locate distributed-object services; it is uncommon outside GNUstep deployments.
lookups: 0rank 994
added: 2026-08-28
updated: 2026-08-28
references: IANA service name registry — port 538

Something wrong?

This record is maintained by the engineers who use port 538. 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 2026-08-28.

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 808 in network services →

the 8 most looked-up other ports in network services — 808 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 :538GNUstep Distributed Objects Mapper

Technical Details

Security Information

Related Ports

Port 538GNUstep Distributed Objects Mapper